Data 2

Final Report by Heat Pump Water Heater
Evaluation Standards Subcommittee, Energy Efficiency
Standards Subcommittee of the Advisory Committee for
Natural Resources and Energy

September 11, 2012
Ministry of Economy, Trade and Industry

The heat pump water heater evaluation standards subcommittee deliberated on
evaluation standards, etc. for manufacturers and importers of heat pump water heaters(hereinafter referred to as “manufacturers, etc.”) for the purpose of improving theperformance of these products (the deliberation included the scope, categories, target
fiscal year, target standard values, measurement methods, etc. of heat pump water
heaters covered in this report) and prepared this interim report as follows.
1. Target scope [See Attachment 1]
Heat pump water heaters covered by this time are all of the residential heat pumpwater heaters using CO2 as refrigerant. However, products equipped with a function
to use heat generated by the heat pump not only for hot water supply or heat-retentionof bath water but also for space heating such as floor heating are excluded from thescope.
2. Matters to be considered as evaluation standards for manufacturers, etc.
(1) Target fiscal year [See Attachment 2]
Target fiscal year for the heat pump water heaters is set as FY2017.
(2) Categories for setting targets and target standard values [See Attachment 3 andAttachment 4]
Regarding heat pump water heaters shipped by manufacturers, etc. to thedomestic market in the target fiscal year, the weighted average values of energy
consumption efficiency of these products obtained by the method stated in paragraph(3) below, where said weighted average values are calculated using the number of
products shipped in each category as shown in Table 1 per manufacturer, shall not be
below the appropriate target values.

Table 1Category

Standard Energy Consumption Efficiency of Heat Pump Water Heaters
Assumedhouseholdtype

Hot water
storage
capacity

Intended
area

1

With

2
3
4
5
6
7

Heatretentionfunction

Normal area
Standard

Without

Below
240 L

With
Cold area
Without8

1

Number oftanks used
for storing
hot water

Standard
energyconsumption
efficiency

Single

2.8

Multi

2.4

Single

3.0

Multi

2.6

Single

2.3

Multi

2.0

Single

2.6

Multi

2.3

9

With

10

Normal area

11

240 L or12

above,

13

below 320

14

L

Without

With
Cold area

15

Without

16
17Standard
With

18

Normal area

19

320 L or20

above,

21

below 550

Without

With

L

22

Cold area

23

Without

24
25

With

26

Normal area

27
28

550 L or

29

above

30

Without

With
Cold area

31

Without

32
33
34

Fewer family

35

members36

Normal area

Cold area

Single

2.8

Multi

2.8

Single

3.2

Multi

2.8

Single

2.3

Multi

2.0

Single

2.7

Multi

2.3

Single

3.3

Multi

2.8

Single

3.2

Multi

2.8

Single

2.7

Multi

2.3

Single

2.7

Multi

2.3

Single

2.9

Multi

2.5

Single

2.9

Multi

2.5

Single

2.4

Multi

2.1

Single

2.5

Multi

2.2

With

2.4

Without

2.8

With

2.0

Without

2.4

Note 1 “Hot water storage capacity” refers to the capacity of a tank unit which iscapable of storing hot water defined in the “Residential Heat Pump Water
Heaters” of Japanese Industrial Standard C 9220 (hereinafter referred to as JIS
C 9220).
Note 2 “Cold area” refers to a specification of a product which is designed and producedon the assumption that it will be used in an area where the weather is severely
cold in winter, as defined in JIS C 9220.
Note 3 “Heat-retention function” refers to a function which circulates and heats bathwater.

2

(3) Method for measuring energy consumption efficiency [See Attachment 5 andExhibit]
Energy consumption efficiency of a heat pump water heater is the ratio of heat
quantity transferred to circulating hot water to electric power consumption per time
unit when the heat pump is operating. It is expressed as “annual water heating andheat-retention efficiency” in case of heat pump water heaters with a bath water
heat-retention function and as “annual water heating efficiency” in case of those
without said function, both of which shall be measured by the method stipulated by
JIS C 9220 and calculated by the following formulae.
<Those with a bath water heat-retention function>
Annual water
heating andheat-retention
efficiency＝

Heat quantity acquired by hot water used in a year +Heat quantity acquired by bathtub water for heat-retention (MJ)
Annual energy consumption (kWh) × 3.6<Those without a bath water heat-retention function>
Annual water
heating
efficiency＝

Heat quantity acquired by hot water used in a year (MJ)
Annual energy consumption (kWh) × 3.6(4) Items to be indicated, etc.
1) Items to be indicatedItems to be indicated are as follows.
i)
Product name or model nameii) Categoryiii) Energy consumption efficiency (annual water heating and heat-retention
efficiency or annual water heating efficiency)iv) Name of manufacturer, etc.
2) Matters to be complied with
1. Annual water heating and heat-retention efficiency and annual water heating
efficiency shall be indicated up to the first decimal place.
2. Items listed in the paragraph 1) above shall be indicated in catalogues andoperation manuals describing the performance of product at the place which iseasy to see and helps consumers choose products.
3. If a product is equipped with a bath water heat-retention function, annual
water heating and heat-retention efficiency must be indicated. If notequipped with the function, annual water heating efficiency must be
indicated.
4. If a product is intended for cold area, it must be clearly mentioned that the
specification is for use in cold areas, and its annual water heating andheat-retention efficiency or annual water heating efficiency under the cold
area condition shall be indicated.

33. Proposals for energy conservation(1) Actions of Government
1) From viewpoint of aiming at the dissemination of heat pump water heaters withexcellent energy consumption efficiency, efforts shall be made to take necessary
measures such as spreading and enlightenment activities, in order to promoteactions of users and manufacturers, etc.
2) Implementation status of information indication which is to be performed bymanufacturers, etc. shall be checked periodically and continuously. Also,
appropriate law management shall be made so that correct andeasy-to-understand information regarding energy consumption efficiency can beprovided for users.
3) As regards categories for which no product currently exists, necessity of making
such categories and adequacy of their standard values shall be studied based on
the future trend of product development, etc. by manufacturers, etc.
4) Energy efficiency standards based on the Top Runner method is a very effectivemeans to reduce energy consumption of products; therefore, efforts shall be madeto disseminate it internationally by catching appropriate opportunities.
(2) Actions of manufacturers, etc.
1) Efforts shall be made to promote technological development for further energy
saving of heat pump water heaters and to develop products with excellent energy
consumption efficiency.
2) From viewpoint of aiming at the dissemination of heat pump water heaters withexcellent energy consumption efficiency, efforts shall be made to provide
appropriate information to encourage users to select such heat pump water
heaters, for example by using “energy-saving labels”, etc. When using theenergy-saving labels, consideration shall be given to the indicated items so as tobe comprehensible for and not to cause misunderstanding among users.
3) Efforts shall be made to provide users with information about how to use products
in a way that contributes to energy saving.
(3) Actions of users
1) Efforts shall be made to select heat pump water heaters with excellent energy
consumption efficiency through effective use of information such as“energy-saving labels”, etc. At the same time, when using heat pump water
heaters, efforts shall also be made to reduce energy consumption by appropriate
and effective use of them, which includes active use of energy-saving setting, etc.
2) In order to maximize the performance of products, efforts shall be made to selectheat pump water heaters based on the conditions of households and environment
in which products are intended to be used.
(4) Actions of retailers
1) Efforts shall be made to sell heat pump water heaters with excellent energy
consumption efficiency as well as to provide appropriate information to users by

4

utilizing “energy-saving labels”, etc. so that they would select such heat pumpwater heaters. When using the energy-saving labels, consideration shall begiven to the indicated items so as to be comprehensible for and no to cause
misunderstanding among users.
2) For appropriate information provision to users at stores, etc., efforts shall bemade to collect information on energy saving of heat pump water heaters as wellas to train sales people for this purpose.
3) Business operators who sell and build heat pump water heaters into buildings
shall also make efforts to choose and install products with excellent energy
consumption efficiency so that dwellers of the buildings will utilize such water
heaters.

5

Attachment 1

Target Scope of Heat Pump Water Heaters
1. Basic idea
Heat pump water heaters covered by this study are all of the residential heat pumpwater heaters using CO2 as refrigerant.
However, those 1) which are used for special applications, 2) for which technicalmethods for measurement and/or evaluation have not been established and 3) whose
penetration rate in the market is extremely low shall be excluded from the scope, andspecifically products described in the following paragraph 2 are excluded. Note thateven though the following products are not included in the scope, 99% of the heat pumpwater heaters shipped is covered by this study.
2. Products excluded from the scope
Of the residential heat pump water heaters covered by this study, those which use theheat generated by the heat pump not only for water heating and heat-retention for bathwater but also for space heating such as floor heating, etc. are excluded from the scope.
It is because methods for measuring their energy consumption efficiency accounting forthe space heating function have not been established and also because their shipment
volume is extremely low.
* Estimated number of products shipped (FY2009): 5.3 thousand units(Ratio to the total number shipped: Approx. 1.0%)

6

Attachment 2

Target Fiscal Year, etc. of Heat Pump Water Heaters
1. Target fiscal year
In the case of heat pump water heaters, it usually takes approximately 2 to 4 years todevelop a new model; therefore, it is necessary to give consideration so that there are atleast a few opportunities for manufacturers to develop new models by the target fiscal
year. As such, it is reasonable to set the target fiscal year as FY2017, which is 8 years
from the reference fiscal year (FY2009).
2. Improvement in target fiscal year
Improvement ratio in the target fiscal year is estimated to be 27% based on thepremise that the number of products shipped and the product composition of eachcategory in the reference year (actual figures of FY2009) remain unchanged.
<Outline of estimation>(1) Energy consumption efficiency calculated from the actual figures of heat pumpwater heaters shipped in the reference fiscal year (FY2009): 2.49
(2) Energy consumption efficiency per unit calculated by weight-averaging target
standard values with shipment volume of heat pump water heaters expected to
be shipped in the target fiscal year: 3.16
(3) Improvement ratio of energy consumption efficiency
3.16 2.49 × 100 = Approximately 27%
2.49

7

Attachment 3

Categories for Setting Target for Heat Pump Water Heaters
1. Basic idea
Heat pump water heaters shall be classified based on the principles referred to as“the basic idea concerning the development and revision of evaluation standards for
manufacturers, etc. to be considered in relation to the improvement in performance ofspecific equipment” (the 10th Energy Efficiency Standards Subcommittee of theAdvisory Committee for Natural Resources and Energy, revised on June 18, 2007)(hereinafter referred to as “the principles”).
“The basic idea concerning the development and revision of evaluation standards for
manufacturers, etc. to be considered in relation to the improvement in performance ofspecific equipment”- Extract Principle 2: Specific equipment is classified based on certain indices. The indices(basic indices) are those which are deeply related to energy consumption
efficiency such as physical amount and functions, and they are determinedconsidering factors which consumers use as criteria when choosing
products (factors representing consumers’ needs).
Principle 3: Target standard value is determined as one value or by functional formulafor each category based on the basic indices, for which it is feasible andappropriate to target at the same energy consumption efficiency.
Principle 4: When setting categories, additional functions are disregarded in principle.
However, there is a case where, if the energy consumption efficiency of a
product without a certain additional function is set as a target standard
value, other products with the additional function may have to withdraw
from the market because they cannot comply with the target standard
value, despite that market needs for the latter products are thought to behigh. If the probability of such case is high, then it is acceptable to makeanother category (sheet) for those products.
Principle 5: As regards products which are expensive but excellent in energy
consumption efficiency because of using advanced energy saving
technologies, although it is possible to classify them into a separate
category, it is desirable to treat them in the same category with others
wherever possible so that manufacturers can actively sell the productswith excellent energy consumption efficiency.
Principle 6: When setting a target standard value for a category, special products shallbe excluded. However, availability of technologies employed in suchspecial products shall be also reviewed when studying the future efficiency
improvement possibly realized by technology development, etc.

8

2. Specific classification method
Heat pump water heaters shall be classified by the following five factors based on
product features.
- Classification by assumed household type- Classification by hot water storage capacity- Classification by intended area
- Classification by availability of heat-retention function- Classification by the number of hot water storage tanks(1) Classification by assumed household type (standard or fewer family members)
Heat pump water heaters are developed not only for standard households (4family members) but also for households with fewer family members (2 people
households), and measurement methods have also been established for both types.
These household types have differences in the amount of hot water used, and theirmeasurement modes are also different. Thus, products shall be classified by thetype of a household assumed at the time of designing.
(2) Classification by hot water storage capacity
Heat pump water heaters are marketed having water storage capacity that
corresponds to their installation spaces and hot water amount to be used. Basedon the difference in capacity, the heating capability of heat pumps, the heat-up
temperature setting and the heat-up time zone of hot water tanks, etc. vary modelby model, which in turn affect the performance of heat pump water heaters.
Therefore, heat pump water heaters shall be classified by hot water storage
capacity. Main features of heat pump water heaters for standard households
classified by hot water storage capacity are shown in Table 3-1.
As regards heat pump water heaters for households with fewer family members,
they have been introduced in the market with a hot water storage capacity of
approximately 200 L.
Considering the amount of hot water to be used,diversification of the hot water storage capacity cannot be expected hereafter; thus,
the products are not classified by this factor.
(3) Classification by intended area (normal area or cold area)
Heat pump water heaters intended for cold area are, anticipating the use in thesevere winter weather, designed and manufactured differently from those intended
for normal area, and accordingly their evaluation methods are also different. Thus,
heat pump water heaters shall be classified by intended area.
(4) Classification by the availability of heat-retention function (with or without)Heat pump water heaters can be classified into those with a function to circulate
and heat bath water and those without such function. The former needs to apply
heat to bath water to perform its heat-retention function; accordingly, electricenergy consumption of these two types of heat pump water heaters is different.
Thus, they shall be classified by the availability of heat-retention function.

9(5) Classification by the number of hot water storage tanks (single or multiple)
Heat pump water heaters can be classified into those with a single hot water
storage tank and those with multiple hot water storage tanks. The latter isintended to have the hot water storage unit thinner by means of containing
multiple tanks of small capacity, considering the space where the product to beinstalled. Compared with heat pump water heaters with single storage tank,products with multiple tanks have larger heat discharge area; as a result, their
heat-retention performances as well as efficiencies are lowered. Thus, they shallbe classified by the number of hot water storage tanks.
As regards heat pump water heaters for households with fewer family members,
they have been introduced in the market with a hot water storage capacity of
approximately 200 L.
Considering the amount of hot water to be used,diversification of the number of hot water storage tanks cannot be expectedhereafter; thus, the products are not classified by this factor.
Hot water
storage tankunit
Heat pump unit

Table 3-1 General Characteristics based on Hot Water Storage Capacity(For Standard Households)
Maincharacteristics

Tank
capacity

Heating-up time zone

Below 240 L

Besidesduringnighttime,
daytime heating-up is also
performed (according to thetime zone when hot water isused).

240 L or above, below
320 LStandard
Being set at high so that plentyof water can be heated in a shortperiod of time to prevent
running-out of hot water.

Standard

Heating-up
temperature oftank unit

Standard

Effect on
efficiency

Standard
Small

As tank capacity isslightly small, heating-up
temperature is set at highto compensate it.

Slightly small

Effect on
efficiency
Major tank capacitycommercially available

Being set at high in orderto accommodate a larger
family consisting of 5 to 7
members.

Standard

Effect on
efficiency

Heat quantity
discharged from tank

550 L or above

Standard (mainly heating-up during nighttime)

Effect on
efficiency

Heating capability ofheat pump unit

320 L or above, below
550 LStandard

Standard

Standard

Standard

Standard

LargeStandard
180 L

300 L

10

370 L
460 L

550 L

3. Summary of classifications
Based on the indices mentioned in the paragraph 2, categories are set as shown in
Table 3-2 (assumed household type: standard) and Table 3-3 (assumed household type:fewer family members).
Table 3-2 Categories of Heat Pump Water Heaters(Assumed Household Type: Standard)Category

Hot water storage
capacity

Intended area

1

With

2

Normal area

3
4
5

Without
Below 240 L
With

6

Cold area

7

Without

8
9

With

10

Normal area

11
12
13

Without

240 L or above,
below 320 L

14

With
Cold area

15

Without

16
17

With

18

Normal area

19
20
21

Without

320 L or above,
below 550 L

22

With
Cold area

23

Without

24
25

550 L or above

With

26
27

Heat-retentionfunction

Normal area
Without

28

11

Number of hot
water storagetanks
SingleMultiple
SingleMultiple
SingleMultiple
SingleMultiple
SingleMultiple
SingleMultiple
SingleMultiple
SingleMultiple
SingleMultiple
SingleMultiple
SingleMultiple
SingleMultiple
SingleMultiple
SingleMultiple

29

With

30

Cold area

31

Without32

Table 3-3 Categories of Heat Pump Water Heaters(Assumed Household Type: Fewer Family Members)
Category
33
34
35
36

Intended Area
Normal area
Cold area

12

Heat-retentionfunction
With
Without
With
Without

SingleMultiple
SingleMultiple[Reference][Specifications for normal area]
Intendedarea

AssumedHeathousehold retentiontypefunction

Numberof tanks

Below 240 L

240 L orabove, below
320 L

320 L orabove, below
550 L

550 L orabove

SingleCategory 1

Category 9

Category 17

Category 25

Multiple

Category 2

Category 10

Category 18

Category 26

SingleCategory 3

Category 11

Category 19

Category 27

Multiple

Category 4

Category 12

Category 20

Category 28

WithStandard

Without

Normalarea

Fewerfamilymembers

With

Category 33

Without

Category 34[Specifications for cold area]
Intendedarea

AssumedHeathousehold retentiontypefunction

Numberof tanks

Below 240L

240L orabove, below
320L

320L orabove, below
550L

550L orabove

SingleCategory 5

Category 13

Category 21

Category 29

Multiple

Category 6

Category 14

Category 22

Category 30

SingleCategory 7

Category 15

Category 23

Category 31

Multiple

Category 8

Category 16

Category 24

Category 32

WithStandard

Without

Cold area

With
Fewer
familymembers

Category 35

Category 36

Without

13

Attachment 4

Target Standard Values for Heat Pump Water Heaters

1. Basic ideas
Target standard values are set based on the idea of Top Runner method. The specificideas are as follows.
1) Target standard values shall be set for every category that has been defined
appropriately.
2) As for categories where technological advances in the future are expected to
improve the efficiency of products, target standard values shall allow for
improvement as much as possible.
3) Target standard values shall not conflict with each other among categories.

2. Calculation of specific target standard values (standard energy consumption
efficiency)(1) Specific technologies for improving energy consumption efficiency and room for
improvement
When setting target standard values for heat pump water heaters, efficient
improvement technologies which are expected to be applied were studied. The
structure of a heat pump water heater can be divided into the heat pump side for heatingwater and the hot water storage tank and supply circuit side for storing and supplying
hot water. On the one hand, substantial efficiency improvement has so far been madefor the heat pump side, because technologies similar to those adopted in air conditioners,
which have already been designated as Top Runner Equipment, are used. On the other
hand, as regards the hot water storage tank and supply circuit side, improvement can be
expected using energy saving technologies such as (a) improvement of thermal
insulation materials, (b) installation of a circuit for taking out medium temperaturewater and (c) improvement of heating-up control.
Specific contents of thesetechnologies are as follows.
(a) Improvement of thermal insulation (See Figure 3-1)
The function of a hot water storage unit is to store heated-up water and keep it hot
until it is supplied and used. Therefore, thermal insulation of this unit greatly
contributes to the energy saving of heat pump water heaters, and covering up the tankbody with a thermal insulation material is commonly-used as a technique to realize it.
Improvement can be achieved through controlling heat discharge from the hot water
storage tank by means of using a highly-efficient thermal insulation material such as
vacuum thermal insulation material in addition to conventional expanded polystyrene
thermal insulation materials (foamed polystyrene).

14

Vacuum thermal insulation

Tank

Front

Tank

Foamed polystyrene

Heat discharge

Without vacuum thermal
insulation materialWith vacuum thermal
insulation material

Figure 3-1 Image of Improvement of Thermal Insulation of
Hot Water Storage Tank (Example)(b) Installation of a circuit for taking out medium temperature water (See Figure 3-2)
A tank equipped in a hot water storage unit has a structure where high temperature
hot water stays at the upper part and colder water stays at the lower part, and there is alayer of medium temperature water between them. When performing heat-retention ofbath water, the high temperature hot water in the tank is used; consequently, thevolume of the medium temperature water increases. If this medium temperature water
is supplied to the heat pump and heated, the efficiency deteriorates. However, the hotwater heat and heat-retention efficiency can be improved by taking out this water
preferentially to be used at lavatory, shower, kitchen, etc.,
Circuit for taking out medium temperature water
Faucet

Hot water supply

Mixingvalve

Hightemperature
hot water

Heat pumpunit

Mediumtemperature
water

ShowerMixing
valve

Water

Pressure
reduction
valve

Water supply

Figure 3-2 Circuit for Taking-out Medium Temperature Water

15

(c) Improvement of heating-up control
Heat pump water heaters generally make hot water at night (11:00 p.m. to 7:00 a.m.).
By mixing the high temperature hot water stored in the tank with low temperature tap
water, it supplies hot water at a certain temperature which is preset by a remotecontroller. Many heat pump water heaters are equipped with a learning function
which is unique to each manufacturer to estimate a hot water amount used in a day andto heat water at an appropriate temperature, thereby reducing the loss caused by heat
discharge.
At the same time, they constantly monitor the hot water amount in their tank unit aswell as the hot water amount used. If it is found that the hot water amount stored in
the tank unit is not enough as a result of large amount of hot water use, the heat pumpstarts operating as appropriate to perform additional heating-up.
Further
improvement of efficiency can be expected from the advancement of control technologies
such as timing of heating-up in daytime and nighttime and setting of the end of heat-up.
(2) Specific target standard values
According to the categories of heat pump water heaters, the Top Runner values wereobtained from actual measured values (FY2009) and estimated values of annual water
heating and heat-retention efficiency (in case of products with a bathwater
heat-retention function) and annual water heating efficiency (products without abathwater heat-retention function), then the target standard values were set according
to the status of each category and taking into account the improvement expected to bemade by the target fiscal year. When doing this, products were divided into 4 groups
based on the ideas described in (A) to (D) below. Specific target standard values are asshown in Table 4-1 and Table 4-2.
(A) A major group corresponding to approximately 90% of the total number of products
shippedCategory

17
18
19

Hot water
storage capacity

320 L orabove, below
550 L

Intendedarea

Heat-retention

Number of hot

functionwater storage tanks

Shipment
ratio

Normalarea

WithSingle68.6%

Multiple

12.9%

Single

8.7%

Without

For heat pump water heaters belonging to this major group, elemental technologies
have actively been introduced. Based on this fact, Top Runner values are obtained
from the actual measurement values, and as much as 3 to 12% of improvement from the
Top Runner values by the target fiscal year is determined. Besides 1% improvement at
the heat pump side, the improvement rate may account for (a) 0 to 2% due to theenhancement of thermal insulation materials, (b) 0 to 2% due to the installation of acircuit for taking out medium temperature water and (c) 2 to 7% due to the bettermentof heating-up control at the hot water storage tank and supply circuit side.

16

Annual water heating andheat-retention efficiency[Category 17]

Actualmeasurement
value
Weighted
averagevalue
Targetstandard
value[Category 18]

Annual water heating andheat-retention efficiency

Actualmeasurement
value
Weighted
averagevalue
Targetstandardvalue

Annual water heating efficiency[Category 19]

Actualmeasurement
value
Weighted
averagevalue
Targetstandardvalue

17

(B) A group whose shipment ratio in the total shipment is currently as low as
approximately 3.5% but, as being close to the (A) group, expected to increase due toan anticipated enhancement of product line-up hereafter
Category

9
10
11
25
27

Hot water
storage capacity

240 L or above,
below 320 L

Intendedarea

Heat-retentionfunction

Number of hot water
storage tanks

WithSingleMultiple

Without

SingleWith

SingleWithout

SingleNormalarea

550 L or above

Shipment
ratio

3.5%

Product development or model-change has not actively been implemented so far for
products in this category, since they are marginal products of the main product group.
Based on this fact, Top Runner values are obtained from actual measurement values,
and as much as 4 to 33% of improvement from the Top Runner values by the target
fiscal year is determined. Besides 0 to 5% improvement at the heat pump side, theimprovement rate may account for (a) 1% due to the enhancement of thermal insulationmaterials, (b) 0 to 3% due to the installation of a circuit for taking out medium
temperature water and (c) 2 to 30% due to the betterment of heating-up control at the
hot water storage tank and supply circuit side.
[Category 9]

Annual water heating andheat-retention efficiency

Actualmeasurement
value
Weighted
averagevalue
Targetstandard
value[Category 10]

Annual water heating andheat-retention efficiency

Actualmeasurement
value
Weighted
averagevalue
Targetstandardvalue

18

Annual water heating efficiency[Category 11]

Actualmeasurement
value
Weighted
averagevalue
Targetstandardvalue

Annual water heating andheat-retention efficiency[Category 25]

Actualmeasurement
value
Weighted
averagevalue
Targetstandardvalue

Annual water heating efficiency[Category 27]

Actualmeasurement
value
Weighted
averagevalue
Targetstandardvalue

19

(C) A group of products made for standard households but with small hot water storage
capacity, products made for households with fewer family members and products
made for use in cold areas.
Category

AssumedhouseholdHot water
storage capacity13Standard

Below 240 L

33

Fewer family
members–

Standard

320 L or above,
below 550 L

21
23

Intendedarea

Heat-retentionfunction

Number of hot water
storage tanks

With
Without

SingleSingle

With

–

With

SingleWithout

SingleNormal
area
Cold
area

Shipment
ratio

1.0%

5.3%

The shipment ratio of products for standard households but with small hot water
storage capacity due to restrictions on installation places and of products for householdswith fewer family members is as low as approximately 1% in the total shipment.
Meanwhile, the shipment ratio of products which are the only ones available in themarket among those intended for cold area is also as low as approximately 5.3% in the
total shipment. Therefore, the Top Runner values of actual measurement values are
directly set as the Top Runner values in the target fiscal year for these products.
[Category 1]

Annual water heating andheat-retention efficiency

Actualmeasurement
value
Weighted
averagevalue
Targetstandardvalue

Annual water heating efficiency[Category 3]

Actualmeasurement
value
Weighted
averagevalue
Targetstandardvalue

20

Annual water heating andheat-retention efficiency[Category 33]

Actualmeasurement
value
Weighted
averagevalue
Targetstandard
value[Category 21]
Actualmeasurement
value

Annual water heating andheat-retention efficiency

Weighted
averagevalue
Targetstandardvalue

Annual water heating efficiency[Category 23]

Actualmeasurement
value
Weighted
averagevalue
Targetstandardvalue

21

(D) A group in which products do not exist in data of the reference fiscal year (FY2009)
Since actual measurement values of this group of products are not available, theTop Runner values in the target fiscal year were estimated using the ratios in othercategories (See Table 4-1). When doing this, fraction numbers were rounded up inorder to further promote energy saving. Details are as per (1) to (7) below, which arecorresponding to the numbers listed in Table 4-1.
(1) Estimation method of products for normal area, for standard household and withmultiple tanks:
The ratio of target standard values (3.3:2.8) of (a) single-tank type and (b)multi-tank type of products whose capacity is 320 L or above and below 550 L andwhich are equipped with a heat-retention function is applied to the relation of thetarget standard value of single-tank products to the value of multi-tank products
sharing the same capacity category and the same heat-retention function category.
* Category 2, 4, 12, 20, 26 and 28 fall under the case of (1).
(2) Estimation method of products for cold area, for standard household, with aheat-retention function and with single tank:
The ratio of target standard values (3.3:2.7) of products (a) intended for normal areaand (d) intended for cold area whose capacity is 320 L or above and below 550 L isapplied to the relation of the target standard value of products intended for normal
area to the value of products intended for cold area sharing the same capacitycategory.
* Category 5, 13 and 29 fall under the case of (2).
(3) Estimation method of products for cold area, for standard household, without aheat-retention function and with single tank:
The ratio of target standard values (3.2:2.7) of products (c) intended for normal areaand (e) intended for cold area whose capacity is 320 L or above and below 550 L isapplied to the relation of the target standard value of products intended for normal
area to the value of products intended for cold area sharing to the same capacitycategory.
* Category 7, 15 and 31 fall under the case of (3).
(4) Estimation method of products for cold area, for standard household and withmultiple tanks:
The ratio of target standard values (3.3:2.8) of (a) single-tank type and (b)multi-tank type of products intended for normal area whose capacity is 320 L orabove and below 550 L and which are equipped with a heat-retention function isapplied to the relation of the target standard value of single-tank products intended
for cold area to the value of multi-tank products intended for cold area sharing thesame capacity category and the same heat-retention function category.
* Category 6, 8, 14, 16, 22, 24, 30 and 32 fall under the case of (4).
(5) Estimation method of products for normal area, for household with fewer family
members and without a heat-retention function:
The ratio of target standard values (2.8:3.2) of single-tank products (f) with aheat-retention function and (g) without a heat-retention function which are forstandard household and whose capacity is 240 L or above and below 320 L is applied
to the relation of the target standard value of products with a heat-retentionfunction to the value of products without the function sharing the same intended
area category and the same assumed household category.
* Category 34 falls under the case of (5).

22

(6) Estimation method of products intended for cold area, for household with fewer
family members and with a heat-retention function:
The ratio of target standard values (3.3:2.7) of single-tank products (a) intended fornormal area and (d) intended for cold area which are for standard household andequipped with a heat-retention function and whose capacity is 320 L or above andbelow 550 L is applied to the relation of the target standard value of products
intended for normal area, for household with fewer family members and with aheat-retention function to the value of products intended for cold area sharing thesame assumed household category and the same heat-retention function category.
* Category 35 falls under the case of (6).
(7) Estimation method of products intended for cold area, for household with fewer
family members and without a heat-retention function:
The ratio of target standard values (3.2:2.7) of single-tank products (c) intended fornormal area and (e) intended for cold area which are for standard household andequipped with a heat-retention function and whose capacity is 320 L or above andbelow 550 L is applied to the relation of the target standard value of products
intended for normal area, for households with fewer family members and without aheat-retention function to the value of products intended for cold area sharing thesame assumed household category and the same heat-retention function category.
* Category 36 falls under the case of (7).

23

Table 4-1

Target Standard Values for Heat Pump Water Heaters[Products intended for normal area]
Intendedarea

Assumedhousehold

Heatretentionfunction

240 L or
320 L orNumber Below 240 L
above, below above, below
of tanks
320 L
550 L
Category 1

Category 9

Category 17

Category 25

(C)

(B)

(A)

(B)

2.8

2.8 (f)

3.3 (a)2.9

Category 2

Category 10

Category 18

Category 26(D) (1)(B)(A)(D) (1)

2.4

2.8

2.8 (b)2.5

Category 3

Category 11

(C)

(B)

(A)

(B)

3.0

3.2 (g)3.2 (c)2.9

Category 4

Category 12

Category 20

Category 28(D) (1)(D) (1)(D) (1)(D) (1)

2.6

2.8

2.8

2.5

SingleWith
Multiple

Standard

SingleWithout

Normalarea

Multiple

550 L orabove

Category 19 Category 27

Category 33
Fewerfamilymembers

(C)

With

2.4
Category 34
Without(D) (5)
2.8[Products intended for cold area]
Intendedarea

Assumedhousehold

Heatretentionfunction

Numberof tanks

Single240 L or
320 L orBelow 240 L above, below above, below
320 L
550 L
Category 5

Category 13

Category 21

Category 29(D) (2)(D) (2)(C)(D) (2)2.3

2.3

2.7 (d)2.4

Category 6

Category 14

Category 22

Category 30(D) (4)(D) (4)(D) (4)(D) (4)

2.0

2.0

2.3

2.1

Category 7

Category 15

Category 23

Category 31(D) (3)(D) (3)(C)(D) (3)2.6

2.7

2.7 (e)2.5Category 8

Category 16

Category 24

Category 32(D) (4)(D) (4)(D) (4)(D) (4)

2.3

2.3

2.3

2.2

With
Multiple
Standard

SingleWithout

Cold
area

Multiple

550 L orabove

Category 35(D) (6)

With

2.0

Fewer
familymembers

Category 36(D) (7)

Without

2.4

24

AssumedhouseholdCategory

Table 4-2 Target Standard Values for Heat Pump Water Heaters per Category
Hot
water
storage
capacity

HeatIntended
Retentionarea
function

1

Numberof hotwater
storagetanks[Reference
fiscal year][Reference
fiscal year][Targetfiscal year]

Weighted
averagevaluesTop
RunnervaluesTargetstandard
valuesSingle2.30

Improvementfrom Top
Runnervalue [%]

2.8

Improvementfromweighted
averagevalues [%]

22

With

2

area

3

2.4

Multiple

NormalSingle3.00

3.0

Without

4

Below
240 L

5

Multiple

2.6

Single2.3

Multiple

2.0

Single

2.6

Multiple

2.3

With

6

Cold
area

7

Without

89Single

2.37

2.5

2.8

12

18

Multiple

2.10

2.1

2.8

33

33

Single

3.00

3.0

3.2

7

7

With

10

Normal

11

240 L
or
above,
below
320 L

12
13
14

16

Without
Multiple

2.8

Single2.3

Multiple

2.0

Single

2.7

Multiple

2.3

With

Cold

Standard

15

area

area
Without

17

Single

2.55

3.1

3.3

6

29

Multiple

2.19

2.5

2.8

12

28

Single

3.00

3.1

3.2

3

7

With

18
19
20
21
22

Normal320 Lorabove,
below
550 L

area
Without

Single

2.03

2.7

33

With

2.3

Multiple

Cold
area

23

2.8

Multiple

Single

2.60

2.7

4

Without

24
25
26
27

2.3

Multiple

550 L
or
above

Single

2.40

2.5

2.9

area

Single

28

30

21

4

4

2.5

Multiple

Normal

2.80

2.8

2.9

Without

29

16

With

Cold
area

Multiple

2.5

Single

2.4

Multiple

2.1

With

25

31

Single2.5

Multiple

2.2

Without32

35
36

Normalmembers

34

Fewer family

33

area
Cold
area

Total

With

2.40

2.4

Without

2.8

With

2.0

Without

2.4
2.49

26

2.88

3.16

10

27

Attachment 5

Energy Consumption Efficiency of Heat Pump Water Heaters and the Measuring
Method
1. Basic idea
For the measurement of energy consumption efficiency of heat pump water heaters,
the measuring method based on actual usage, which is stipulated in JIS C 9220
“Residential Heat Pump Water Heaters” (hereinafter referred to as JIS C 9220) of year
2011, shall be adopted.
2. Specific energy consumption efficiency and the measuring method(1) Energy consumption efficiency
Energy consumption efficiency of a heat pump water heater is the ratio of heat
quantity transferred to circulating hot water to electric power consumption per time
unit when the heat pump is operating. It is expressed as “annual water heating andheat-retention efficiency” in case of heat pump water heaters with a bath water
heat-retention function and as “annual water heating efficiency” in case of those
without said function, both of which shall be measured by the method stipulated by JIS
C 9220 (see Attachment) and calculated by the following formulae.
<Those with a bath water heat-retention function>
Annual water
heating andheat-retention
efficiency＝

Heat quantity acquired by hot water used in a year +Heat quantity acquired by bathtub water for heat-retention (MJ)
Annual energy consumption (kWh) × 3.6<Those without a bath water heat-retention function>
Annual water
heating
efficiency＝

Heat quantity acquired by hot water used in a year (MJ)
Annual energy consumption (kWh) × 3.6

27

Attachment
Methods for Measurement and Calculation of Annual Water Heating andHeat-retention Efficiency (for Products with a Bathwater Heat-retention Function)
1. Procedures for measurement and calculation
heat-retention efficiency

ofannualwater

heatingandA residential heat pump water heater is composed of a “heat pump unit” and a “hotwater storage unit”.
Heat pump unit
Electricity

Hot water
storage unit

Compressor

Refrigerant
cycle

Expansionvalve

Lavatory

Waterheating

Air heatexchanger

Water heatexchanger

Heat absorbed
from air

Hot water supply
Kitchen

Bath

Pump

Water supply

Composition of Residential Heat Pump Water Heater● Specific procedures for measurement and calculation of energy consumption efficiency are
as follows.
[Procedure (1)] Calculation of “water heating and heat-retention mode efficiency” of asystem as a whole- The measurement is performed in “water heating and heat-retention mode (under the
winter condition)” according to an actual usage.

[Procedure (2)] Calculation of “heat pump unit efficiency”- The measurement is performed under 6 temperature conditions (i.e. standard heating
conditions (middle season, summer and winter), high temperature heating conditions(winter and frosting season) and water heating mode heating condition).
* For products intended for cold area, an additional measurement shall be performed
under a high temperature heating condition for winter season in cold area.

[Procedure (3)] Calculation of “annual water heating and heat-retention efficiency”(1) A factor is obtained from “water heating and heat-retention mode efficiency” and “heatpump unit efficiency” under the winter condition. With the factor, “water heating andheat-retention mode efficiency” under each outside temperature is calculated.
(2) “Annual heat quantity of water heating and heat-retention” is calculated from thenumber of days when applicable outside temperature occurs and the in-coming watertemperature.
(3) “Energy consumption” at each outside temperature is obtained from “heat quantity ofwater heating and heat-retention mode” and the “water heating and heat-retention mode
efficiency” of each outside temperature, and they are summed up to obtain “annual
energy consumption”.
(4) “Annual water heating and heat-retention efficiency” is calculated from the “annual heat
quantity of water heating and heat-retention” and the “annual energy consumption”.

2. Outline of methods for measurement and calculation of annual water heating andheat-retention efficiency
Temperature
condition

Items

Outline- In the case of products with a bathwater heat-retention function -Air temperature: Dry bulb 7.0±1°C, wet bulb 6.0±0.5°C
Water temperature: Water supply temperature 9.0±2.0°C

Heat pump unit

Return from HP
Go to HP
Water supply
Hot water supply
Go to bath
Return from bath

Water supply
unit

Test instrument
Operational state
Heat quantity ofwater heating
andheat-retention

Test procedures

Procedure (1) Calculation of “water heating and heat-retention mode efficiency” of a system as a whole

Hot water storage unit
Flow meter
Temperature gauge

BathTest room air conditioner

Test facility, sample product for test and, placement of measuring instruments for a heat pump water heater(Example)

Measurement instrumentsa) Temperature gauges to measure temperatures of water supply and hot water supply, and a flow meter tomeasure the volume of hot water supplyb) Temperature gauges to measure temperatures of hot-water going-to-bath and returning-from-bath, and aflow meter to measure the volume of hot water returning from bath.
c) An integrating wattmeter to measure electric power consumption of a residential heat pump water heaterd) Temperature gauges to measure temperatures of water going to and returning from the heat pump unit,
and a flow meter to measure the volume of water going to the heat pump unit.
e) A thermocouple to monitor the heat quantity of hot water remaining in the hot water storage tank.
Test shall be conducted by operating a residential heat pump water heater at the rated frequency and the rated
voltage (the tolerance is within ±2% for each rating).
A residential heat pump water heater shall be operated with an as-shipped operation setting. However, in caseof a product equipped with a learning control function, it shall be operated with an as-shipped operation setting
until the operation is stabilized in a water heating and heat-retention mode. If remaining hot water amountafter the operation is stabilized is below 100 L at 40°C, the operation setting must be changed so that theremaining hot water amount becomes 100 L or above at 40°C. How to set this operation setting for test shallbe documented in a technical data. Heating-up temperature of the operation setting for test must be the sameor above the heating-up temperature when the product is in a stable state after being operated in the water
heating and heat-retention mode with the as-shipped operation setting.
Water heating and heat-retention mode: “Standard Usage Mode for Bathwater Heating of Bath Furnace with
Hot Water Supply Function” of JIS S 2072 is adopted (Attachment 1).
* To enhance the accuracy of measuring heat quantity of water heating, a usage mode whichsummarizes successive operations having the same intended usage is prepared (Attachment 2).
(As for a water heating mode, TS S 0003 “Standard Usage Mode of Water Heating Appliances used for Kitchens,
Lavatories, Showers and Baths” is adopted.)
Water heating performance test is conducted according to the following schedule, and then the heat quantity ofwater heating and heat-retention and the electric energy consumption on the third day are measured. The
heat quantity of water heating on each day must be within the range of ±5%, and the heat quantity ofheating-up on the second and third days must be within the range of ±5%.
<Presumed time>
7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 0 1 2 3 4 5 6(1)(2)

Heating-up
Water heating, heat-retention

Water heating, heat-retention
(3)

(4)

Water heating, heat-retention
Time zone for measuring heat
quantity of heating-up

Time zone for measuring
electric energy consumption

ItemsOutline- In the case of products with a bathwater heat-retention function Water heating and heat-retention mode efficiency is calculated by the following formula.

CMW1

QMW1
PMW1 3.6

Here:
CMW1: Water heating and heat-retention mode efficiency
QMW1: Heat quantity of water heating and heat-retention mode (MJ) ← Total of water heating’s heat
quantity and heat-retention’s heat quantity of one day
PMW1: Energy consumption in water heating and heat-retention mode (kWh) ← Energy consumption of one
day when operating in water heating and heat-retention mode
3.6:
Factor to convert kWh to MJ
Heat quantity of water heating

Q

te
j ts

Calculation formula

Procedure (1) Calculation of “water heating and heat-retention mode efficiency”

Water heating and heat-retention mode efficiency

Here:
Q:
j:
Tm :
ts :
te :
Ti :
ρ:
cp:
qm:
tm :

Tm Ti

qm

c p tmHeat quantity of each water heating mode (kJ)Section numbered for each measurement interval
Hot water supply temperature (°C)
Time when hot water supply starts
Time when hot water supply ends
Water supply temperature when simultaneously measuring each hot water supply temperature (°C)
Water density at each hot water supply temperature (kg/L)……(from Table A.4)
Average specific heat of water 4.1796 (kJ/kg･°C)……(constant value)
Flow rate in measurement interval (L/min)
Measurement interval (min)Heat quantity of heat-retention

Qｋ

te
j ts

Tok

Tik

qｋ

c p tｋHere:
Q k: Heat quantity of each heat-retention mode (kJ)j:Section numbered for each measurement interval
ToK: Temperature of water going to bath (°C)
ts: Time when valid heat quantity of water heating starts
te: Time when hot water supply ends
Tik: Temperature of hot water returning from bath when simultaneously measuring temperature of hot
water going to bath (°C)ρ:
Water density at temperature of water going to bath (kg/L)…… (from Table A.4)
cp: Average specific heat of water 4.1796 (kJ/kg･°C)…… (constant value)
qk: Flow rate in measurement interval (L/min)tm: Measurement interval (min)Accumulation shall be made as far as the condition of ToK > Tik is right.

ItemsOutline- In the case of products with a bathwater heat-retention function Unit: °C
Temperature setting ofgoing-out hot water

Temperature conditions

Conditions
Standard heating
condition for middle
seasonStandard heating
condition for summer
Standard heating
condition for winterHigh temperature
heating condition for
winterHigh temperature
heating condition for
frosting season
High temperature
heating condition for
winter in cold area

Dry bulb
temperatureStandard heating-up
temperature

16

12

17

(2)

25

21

24

(3)

7

6

9

(1)

High heating-up temperature
for winter

7

6

9

(4)

High heating-up temperaturefor frosting season

2

1

5

(5)

–7

–8

5

(6)

7

6

9

(8)

Standard heating-up
temperatureStandard heating-up
temperature

High heating-up
temperature for winter incold area
Heating-up temperatureduring the water heating
mode performance test

* Performance test under the high temperature heating condition for winter in cold area shall be performed for
products intended for cold area.

Test

procedure

Flow meter

Water supply
unit

Heat pump unit

Temperature gauge

Test room air conditioner

Test instrument

Test facility and placement of sample product for test (Example)a) Measurement under steady condition
Once the test condition reaches a steady state, allow the unit to operate for at least one hour, and thenmeasurements shall be taken 7 times at 5 minute interval.
b) Measurement under transient condition
Heating capacity test of heat pump while in a state accompanying defrosting.
“Heat pump unit efficiency” under each condition is obtained from dividing heating capacity, as calculated per
the following formula, by electric power consumption in a steady state. Thus, the heating capacity is
calculated by the following formula, using the average of measured values.

Φ
Calculation formula

Procedure (2) Calculation of “heat pump unit efficiency”

Water heating modeheating condition

Water
Procedure (3)temperature
Wet bulb
In-coming water COP performance
temperaturetemperatureline No.

Inlet air temperature(T2T1 )・qr・c p

Here:
Φ: Total heating capacity of a heat pump, which is calculated from the heat exchange amount of a heatexchanger of the use side.
T1: Inlet water temperature of a heat exchanger of the use side (°C)
T2: Outlet water temperature of a heat exchanger of the use side (°C)
cp: Specific heat of water (J/kg°C)
qr: Mass flow rate of a heat exchanger of the use side (kg/s)→Water heating and heat-retention mode energy consumption efficiency, CHMT1, is “heat pump unit efficiency”
at the heating-up temperature of water heating mode performance test.

Water heating andheat-retention efficiency
factor of a heat pump

Items

Outline- In the case of products with a bathwater heat-retention function -Water heating and heat-retention efficiency factor of a heat pump, FHM1, is the ratio of water heating andheat-retention mode efficiency, CMW1, obtained in the procedure (1) to water heating and heat-retention mode energy
consumption efficiency, CHMT1, obtained in the procedure (2). The factor is calculated by the following formula.
CMW1
FHM1
CHMT1
Here:
CHMT1: Water heating and heat-retention mode energy consumption efficiency← From the procedure (2)CMW1: Water heating and heat-retention mode efficiency← From the procedure (1)Temperature condition

Temperaturecategoryj

Outsidetemperature
tj °C

Number of
days
dj d

Temperaturecategoryj

Outsidetemperature
tj °C

Number of
days
dj d

Temperaturecategoryj

Outsidetemperature
tj °C

Number of
days
dj d

1

–10

0

16

5

17

31

20

15

2

–9

0

17

6

17

32

21

15

3

–8

0

18

7

15

33

22

13

4

–7

0

19

8

15

34

23

14

5

–6

0

20

9

13

35

24

11

6

–5

0

21

10

12

36

25

12

7

–4

0

22

11

11

37

26

13

8

–3

0

23

12

12

38

27

14

9

–2

0

24

13

10

39

28

15

10

–1

0

25

14

12

40

29

7

11

0

1

26

15

13

41

30

2

12

1

1

27

16

13

42

31

0

13

2

5

28

17

14

43

32

0

14

3

9

29

18

15

–

–

15

4

15

30

19

14

365

I)

Outside temperature

43

QMA1＝

QM1 (tj )・djIV) Energy consumption when outside temperature is tj, PM1 (tj),is calculated by dividing the heat quantity of water heatingand heat-retention when outside temperature is tj, QM1 (tj),by the water heating and heat-retention mode efficiency, CM1(tj). Then, annual water heating and heat-retention modeenergy consumption, PMA1, is calculated by multiplying theenergy consumption calculated above by the number of days
when outside temperature is tj, then by totaling them.
43

PMA1

Q M1 (tj )djC M1 (tj ) 3.6

V) Annual water heating and heat-retention efficiency, CMA1, iscalculated by the following formula.
j 1

CMA1

QMA1
PMA1 3.6

Water temperature (°C)

j ＝1

Number of days (d)Calculation formula

From the heat pump unit efficiency under each condition(COP) obtained in the procedure (2), heat pump unit
efficiency (COP) per outside temperature and per going-out
hot water temperature is calculated (Right figure: COP
performance line).
II) From the water heating and heat-retention efficiency factor
of a heat pump, FHM1, and the heat pump unit efficiency peroutside temperature and going-out hot water temperature,
water heating and heat-retention mode efficiency, CM1 (tj),per outside temperature is calculated (Right figure: water
heating and heat-retention mode efficiency performanceline).
III) Annual heat quantity of water heating and heat-retention,
QMA1, is calculated by multiplying the heat quantity ofwater heating and heat-retention when outside temperature
is tj, QM1 (tj), by the number of days when outside
temperature is tj, then by totaling them.

–

Total

Water heating’ and heat-retention mode efficiency

Procedure (3) Calculation of “annual water heating and heat-retention efficiency”

Number of days when each of listed average outside nighttime temperature occurs in a year.

Hot water supply temperature(Lavatory, kitchen, bath, shower)

Water supply
temperature (°C)

Outside temperature tj (°C)

Here:
CMA1: Annual water heating and heat-retention efficiency when performing water heating and heat-retention inwater heating and heat-retention mode
QMA1: Annual heat quantity of water heating and heat-retention mode (MJ)
PMA1: Annual water heating and heat-retention mode energy consumption (kWh)3.6:
Factor to convert kWh to MJ

Products forhouseholds with fewer
family members

Items

Outline- In the case of products with a bathwater heat-retention function -Evaluation shall be made after replacing the water heating and heat-retention loads by the ones according towater heating and heat-retention mode for household with fewer family members (Stipulation).
* A usage mode which lists operations in water heating and heat-retention mode for households with fewer
family members as well as a usage mode which summarizes successive operations having the same intended
usage listed in the aforementioned mode are prepared (Attachment 3).

Annual water heating and heat-retention efficiency is calculated by using the following table for outside
temperature, water supply temperature and number of days when each outside temperature occurs. Annual
water heating and heat-retention efficiency for normal area shall also be indicated for reference.

Products intended for cold area

OthersII Area (Morioka)
Temperaturecategoryj

Outsidetemperature
tj °C

Number of
days
dj d

Temperaturecategoryj

Outsidetemperature
tj °C

Number of
days
dj d

Temperaturecategoryj

Outsidetemperature
tj °C

Number of
days
dj d

1

–10

0

16

5

10

31

20

11

2
3

–9
–8

1
2

17
18

6
7

11
11

32
33

21
22

9
9

4

–7

3

19

8

9

34

23

9

5

–6

5

20

9

10

35

24

6

6
7

–5
–4

8
11

21
22

10
11

9
10

36
37

25
26

4
1

8

–3

13

23

12

11

38

27

0

9

–2

15

24

13

11

39

28

0

10
11

–1
0

16
20

25
26

14
15

12
13

40
41

29
30

0
0

12

1

16

27

16

15

42

31

0

13

2

13

28

17

15

43

32

0

14
15

3
4

11
9

29
30

18
19

13
13

–

–

–
365

Total

To calculate annual water heating and heat-retention efficiency of products intended for cold area, heat pumpunit efficiency of product under the following condition shall be actually measured.
Unit: °C
Condition

Temperature setting ofgoing-out hot waterHigh temperature heating
condition for winter in cold area

High heating-up
temperature in cold area

Inlet air temperature

Water temperature

Dry bulb
temperature

Wet bulb
temperature

In-coming watertemperature

–7

–8

5

Attachment 1
Water heating and heat-retention mode

Heat quantities are those in the winter condition.

No.

Usage

Start
time

Heat quantity of hot
water heating MJHeat quantity ofheat-retention MJ

Flow rate
L/min

1

Lavatory

7:00:00

1.286

–

5

10.00

2

Lavatory

7:02:30

0.107

–

5

0.83

3

Lavatory

7:03:10

0.107

–

5

0.83

4

Lavatory

7:04:20

0.107

–

5

0.83

5

Lavatory

7:05:00

0.107

–

5

0.83

6

Kitchen

8:15:00

0.643

–

5

5.00

7

Kitchen

8:16:30

0.107

–

5

0.83

8

Kitchen

8:17:10

0.107

–

5

0.83

9

Kitchen

8:27:20

3.214

–

5

25.00

10

Kitchen

8:34:20

0.321

–

5

2.50

11
12
13

Kitchen
Kitchen
Kitchen

13:00:00
13:01:30
13:02:10

0.643
0.107
0.107

–
–
–

5
5
5

5.00
0.83
0.83

14

Kitchen

13:07:20

1.286

–

5

10.00

15

Kitchen

13:10:20

0.321

–

5

2.50

16

Kitchen

18:15:00

0.643

–

5

5.00

17

Kitchen

18:16:30

0.107

–

5

0.83

18

Kitchen

18:18:40

0.643

–

5

5.00

19

Kitchen

18:24:40

0.643

–

5

5.00

20

Kitchen

18:26:10

0.107

–

5

0.83

21

Kitchen

18:26:50

0.107

–

5

0.83

22

Kitchen

18:27:30

0.107

–

5

0.83

23

Kitchen

18:32:40

0.321

–

5

2.50

24

Kitchen

18:33:40

0.107

–

5

0.83

25

Kitchen

18:34:20

0.107

–

5

0.83

26

Bath

19:40:00

23.143–10-15

180.0027

Kitchen

20:00:00

1.286

–

5

10.00

28

Kitchen

20:02:30

0.321

–

5

2.50

29

Shower

20:08:00

2.571

–

10

20.00

30

Kitchen

20:12:00

0.321

–

5

2.50

31

Kitchen

20:13:00

0.107

–

5

0.83

32

Kitchen

20:18:10

0.321

–

5

2.50

33

Kitchen

20:19:10

0.107

–

5

0.83

34

Kitchen

20:19:50

0.107

–

5

0.83

35

Heat-retention

20:27:00

–

1.020

–

–

36

Shower

20:30:00

6.428

–

10

50.00

37

Kitchen

20:36:00

0.107

–

5

0.83

38

Kitchen

20:36:40

0.107

–

5

0.83

39

Kitchen

20:37:20

0.107

–

5

0.83

40

Kitchen

20:38:00

0.107

–

5

0.83

41

Heat-retention

20:57:00

–

0.530

–

–

42

Heat-retention

21:27:00

–

0.530

–

–

43

Heat-retention

21:57:00

–

0.530

–

–

44

Lavatory

22:00:00

1.286

–

5

10.00

45

Lavatory

22:02:30

0.107

–

5

0.83

46

Lavatory

22:03:10

0.107

–

5

0.83

47

Lavatory

22:03:50

0.107

–

5

0.83

48

Shower

22:14:00

2.571

–

10

20.00

49

Lavatory

22:16:30

0.107

–

5

0.83

50

Lavatory

22:17:10

0.107

–

5

0.83

51

Heat-retention

22:27:00

–

1.020

–

–

52

Shower

22:32:20

6.428

–

10

50.00

53

Lavatory

22:39:20

0.321

–

5

2.50

54

Lavatory

22:40:50

0.107

–

5

0.83

55

Lavatory

22:43:00

0.643

–

5

5.00

56

Lavatory

22:45:00

0.107

–

5

0.83

58.5944.120–

455.74Total

Hot water supply
amount L

Attachment 2
Water heating and heat-retention mode
(when operations for the same intended usage are summarized)
Heat quantities are those in the winter condition.
No.

Usage

Start time

Heat quantity of hot
water heating
MJ

Heat quantity ofheat-retention MJ

Flow rate
L/min

Hot water supply
amount L

1

Lavatory

7:00:00

1.713

–

5

13.32

2
3
4

Kitchen
Kitchen
Kitchen

8:25:00
13:05:00
18:25:00

4.392
2.463
2.890

–
–
–

5
5
5

34.16
19.16

5
6
7

Bath
KitchenShower

19:40:00
20:01:00
20:08:00

23.143
1.607
2.571

–
–
–

10-15
5
10

180.0012.50

8
9Kitchen

20:16:00
20:27:00

0.963
–

–
1.020

5
–

7.49
–

22.48

20.00

10

Heat-retention
Shower

20:30:00

6.428

–

10

50.00

11

Kitchen

20:37:00

0.427

–

5

3.32

12
13

Heat-retention

–
–

1.020
0.530

–
–

–

Heat-retention

20:57:00
21:27:00

14
15
16

Heat-retention
Lavatory
Shower

21:57:00
22:02:00
22:14:00

–
1.606
2.571

0.530
–
–

–
5
10

–
12.49

17
18
19

Lavatory

22:17:00
22:27:00
22:32:20

0.213
–
6.428

–
1.020
–

5
–
10

1.66
–
50.00

22:43:00

1.178
58.594

–
4.120

5
–

9.16
455.7420

Heat-retention
ShowerLavatory
Total

–

20.00

Attachment 3
Water heating and heat-retention mode for household with fewer family members
Heat quantities are those in the winter condition.
No.

Usage

Start
time

1

Lavatory

7:00:00

0.643

–

5

5.00

2

Lavatory

7:02:30

0.107

–

5

0.83

3

Lavatory

7:03:10

0.107

–

5

0.83

4

Kitchen

8:15:00

0.129

–

5

1.00

5

Kitchen

8:16:30

0.107

–

5

0.83

6

Kitchen

8:17:10

0.107

–

5

0.83

7

Kitchen

8:27:20

1.286

–

5

10.00

8

Kitchen

8:34:20

0.129

–

5

1.00

9

Kitchen

13:00:00

0.129

–

5

1.00

10

Kitchen

13:01:30

0.107

–

5

0.83

11

Kitchen

13:02:10

0.107

–

5

0.83

12

Kitchen

13:07:20

0.514

–

5

4.00

13

Kitchen

13:10:20

0.129

–

5

1.00

14

Kitchen

18:15:00

0.193

–

5

1.50

15

Kitchen

18:16:30

0.107

–

5

0.83

16

Kitchen

18:18:40

0.257

–

5

2.00

17

Kitchen

18:24:40

0.172

–

5

1.34

18

Kitchen

18:26:50

0.107

–

5

0.83

19

Kitchen

18:27:30

0.107

–

5

0.83

20

Kitchen

18:32:40

0.214

–

5

1.66

21

Kitchen

20:00:00

0.514

–

5

4.00

22

Kitchen

20:02:30

0.129

–

5

1.00

23

Kitchen

20:12:00

0.171

–

5

1.33

24

Kitchen

20:18:10

0.214

–

5

1.66

25

Kitchen

20:37:00

0.171

–

5

1.33

26

Bath

20:40:00

19.285–10-15

150.0027

Shower

21:08:00

2.571

–

10

20.00

28

Heat-retention

21:27:00

–

0.850

–

–

29

Heat-retention

21:57:00

–

0.442

–

–

30

Heat-retention

22:27:00

–

0.442

–

–

31

Shower

22:32:20

6.428

–

10

50.00

32

Lavatory

22:39:20

0.910

–

5

7.08

33

Lavatory

22:42:00

0.214

–

5

1.67

34

Lavatory

22:44:30

0.375

–

5

2.92

35.7371.734–

277.96

Total

Heat quantity of hot
water heating
MJ

Heat quantity ofheat-retention MJ

Flow rate
L/min

Hot water supply
amount L

Water heating and heat-retention mode for household with fewer family members (whenoperations for the same intended usage are summarized)

Heat quantities are those in the winter condition.

No.

Usage

Start
time

Heat quantity of hot
water heating
MJ

Heat quantity ofheat-retention MJ

Flow rate
L/min

Hot water supply
amount L

1

Lavatory

7:00:00

0.856

–

5

6.66

2

Kitchen

8:25:00

1.757

–

5

13.66

3

Kitchen

13:05:00

0.985

–

5

7.66

4

Kitchen

18:25:00

1.156

–

5

8.99

5

Kitchen

20:01:00

0.643

–

5

5.00

6

Kitchen

20:16:00

0.385

–

5

3 00

7

Kitchen

20:37:00

0.171

–

5

1.33

8

Bath

20:40:00

19.285–10-15

150.009

Shower

21:08:00

2.571

–

10

20.00

10

Heat-retention

21:27:00

–

0.850

–

–

11

Heat-retention

21:57:00

–

0.442

–

–

12

Heat-retention

22:27:00

–

0.442

–

–

13

Shower

22:32:20

6.428

–

10

50.00

14

Lavatory

22:43:00

1.498

–

5

11.66

35.7371.734–

277.96

Total

Attachment 6
Heat Pump Water Heater Evaluation Standards Subcommittee,
Energy Efficiency Standards Subcommittee of the Advisory Committee
for Natural Resources and Energy
Meeting History

First Subcommittee Meeting (July 20, 2010)- Disclosure of the Heat Pump Water Heater Evaluation Standards Subcommittee- Current status of heat pump water heaters- Scope of heat pump water heaters- Energy consumption efficiency of heat pump water heaters and its measurement
methodSecond Subcommittee Meeting (March 28, 2012)- Classification of heat pump water heaters- Target fiscal year and target standard values for heat pump water heaters

Third Subcommittee Meeting (April 17, 2012)- Interim report on heat pump water heaters

Attachment 7

Heat Pump Water Heater Evaluation Standards Subcommittee,
Energy Efficiency Standards Subcommittee of the Advisory Committee
for Natural Resources and Energy
List of Members
Chairman

Motoyasu Kamata

Professor Emeritus, The University of Tokyo

Members

Yukie Iino

Researcher, Consumer Lives Research Center,
Japan Consumer’s Association

Tadayoshi Tanaka

General Manager, Technology Planning andManagement Department, The Energy
Conservation Center, Japan(Replaced by committee member Inoue from thesecond meeting)Mamoru Inoue

General Manager, Technology Planning andManagement Department, The Energy
Conservation Center, Japan(Joined from the second meeting)

Shinya Okada

Deputy Chairman, Heat Pump Water Heater
Committee, The Japan Refrigeration and Air
Conditioning Industry Association

Kiyoshi Saito

Professor, Faculty of Science and Engineering,
Waseda University

Masako Sugimoto

Director, Nippon Association of Consumer
Specialists

Hirofumi Daiguji

Associate Professor, Graduate School of Frontier
Sciences, The University of Tokyo

Koichi Takubo

Manager, Business Department, The Federation ofElectric Power Companies of Japan

Chiharu Murakoshi Vice President, Jyukankyo Research Institute Inc.

Reference

Status Quo of Heat Pump Water
Heaters
July 22, 2010
Ministry of Economy, Trade and Industry
Commerce and Information Policy Bureau
Information and Communication
Electronics Division11. What is Heat Pump Water Heater?
Heat pump water heaters
A collective name for water heaters using the principle of heat pump as in the case of air
conditioners. They are considered as products excellent in energy saving performance. There areresidential heat pump water heaters and commercial heat pump water heaters.

* The name “EcoCute” is a registered trade name of the Kansai Electric Power Co.,
Inc., which is used by many companies with the permission of said company.

Features

The heat pump unit ((1) in the right figure) efficiently
makes a large amount of hot water, and then it is stored(storage temperature at 65 to 90℃) in the hot water storage
unit ((2) in the right figure). Hot water is served from thestorage unit when it is used at baths, lavatories, kitchens,etc.
Residential heat pump water heaters generally make hotwater using less expensive nighttime electricity, so theirelectric bill is relatively low.

(2) Hot water
storage unit

Refrigerant used

Heat pump water heaters using HFC (fluorocarbon) as
refrigerant are conventionally available in the market.
However, those using carbon dioxide (CO2) as refrigerant
were developed in 2001, and the demands, especially forresidential models, has been expanding. (Somecommercial models are still using HFC.)(1) Heat pumpunit
2

2. Types of Heat Pump Water Heaters (1)Residential heat pump water heaters
Residential heat pump water heaters are classified into several types according to their tankshape, capacity, function, etc. The capacity ranges from 370 to 460 L in case of products forstandard households (4 family members) and from 150 to 200 L in case of compact tanks (for asingle, 2 family members, etc.).

1. Types by tank shape and capacity<Standard tank><Thin tank><Compact tank><All-in-one type>

2. Types by function
a. Full-auto type
Those equipped with functions of “automatic hot water filling”, “hot water adding”,“automatic heat-retention” and “reheating” for bath.
b. Auto (semi-auto) type
Those equipped with functions of “automatic hot water filling” and “hot water adding” for bath.
c. Hot water supply only type
Those designed only for hot water supply, so they fill a bath with hot water through a faucet.
d. Multifunction type
Those equipped with a floor heating function in addition to a hot water supply function forbath, lavatory, kitchen, etc.
3

3. Types of Heat Pump Water Heaters (2)Commercial heat pump water heaters
Commercial heat pump water heaters are used in commercial facilities such asbuildings, hotels, etc. Following types are available according to their scales and hot
water amount used.
<For small scale buildings>
Clinics, inns,
small welfare facilities, etc.
Restaurants, shops, etc.

<For large scale buildings>
Hospitals, hotels, large welfare
facilities
Sports spa facilities,
meal supply facilities, etc.

4

4. Shipping Quantity of Heat Pump Water Heaters (1)(Residential)
Residential heat pump water heaters
Shipping quantity of residential heat pump water heaters started to rapidly increase in aroundyear 2002 (*), making cumulative shipping quantity reach approximately 2.25 million units.
Shipment quantity in FY2009 is 508 thousand units, and the market size remains at around 500
thousand units likewise in the previous year.
Main manufacturers are the following 12 companies, and there are few imported products soldin the market.
* A “subsidy system” in which the government bears part of the cost to install heat pump water heaters(CO2 refrigerant) was implemented in FY2002. Since then, thanks to this subsidy system in part, thenumber of installed units has rapidly increased.

Main manufacturers of residential products
Corona Corporation
Sanden Corporation
SANYO Electric Co., Ltd.
Daikin Industries, Ltd.
Choshu Industry Co., Ltd.
CHOFU SEISAKUSHO Co., Ltd.
DENSO Corporation
TOSHIBA CARRIER Corporation
Housetec Inc.
Panasonic Corporation
Hitachi Appliances, Inc.
Mitsubishi Electric Corporation(In Japanese alphabetical order)

Transition of shipping quantity ofresidential models (Unit: One thousand units)

600

500 508

500

413

400

350

300

226

200
100
0

3 37

81

131

2001 2002 2003 2004 2005 2006 2007 2008 2009
Data provided by The Japan Refrigeration and Air
Conditioning Industry Association

55. Shipping Quantity of Heat Pump Water Heaters (2)(Commercial)Commercial Heat Pump Water Heaters
Shipping quantity of commercial heat pump water heaters in FY2009 is 3.6
thousand units, and its cumulative shipping quantity is 10 thousand plus units. Its
market size is small compared with that of residential models, occupying only lessthan 1% of the heat pump water heater market as a whole.
Main manufacturers are the following companies, and there are few imported
products.
● Transition of shipping quantity,commercial (Unit: One thousand units)● Main manufacturers of commercial products

Showa Manufacturing Co., Ltd.
Daikin Industries, Ltd.
DENSO Corporation
TOSHIBA CARRIER Corporation
Nihon Itomic Co., Ltd.
Panasonic Corporation
Hitachi Appliances, Inc.
MAYEKAWA MFG. Co., Ltd.
Mitsubishi Electric Corporation(In Japanese alphabetical order)

60
50
40
30
20
10
0

1.6 2.2 3.5 3.6
2001 2002 2003 2004 2005 2006 2007 2008 2009
Data provided by The Japan Refrigeration
and Air Conditioning Industry Association

66. Technology of Heat Pump Water Heaters (1)Principle of making hot water
Using the “principle of heat pump” which is also employed in air conditioners, heat pump water
heaters make hot water through the compression-expansion cycle of refrigerant, store it in a hotwater storage tank and supply it.
(1) A heat pump water heater makes its refrigerant to absorb heat from air through an “air heatexchanger” and compresses the refrigerant with a compressor to bring it into a high temperatureand high pressure state. (2) Then, the heat of the refrigerant is transferred to water through a“water heat exchanger”, and the produced hot water is stored in a hot water storage tank. (3)The refrigerant which lost heat is expanded by an expansion valve to bring it back to a lowtemperature and low pressure state again in which it can easily absorb heat from air. A heatpump water heater is a mechanism repeating this procedure.
* Hot water stored in the hot water storage
unit is kept hot and used according to the
purpose of use.

•In a heat pump unit, hotwater is made throughheat exchange using theheat of air.

Heat pump unit

Air heatexchanger(3)

KitchenCompressor(1)
Absorptionof hear fromair

Hot water supply

Water
heat
exchanger(2)
Refrigerant
cycle

Expansionvalve

Lavatory

Waterheating

Electricity

Hot water
storage unit

Bath

Pump

Water
supply7

7. Technology of Heat Pump Water Heaters (2)Toward further energy saving
To realize further energy saving, efficiency of every component is being enhanced.
(1) As for technologies of the heat pump side, efficiency improvement of heat exchangers,
compressors, etc. is being worked on. (Figure (1) below shows an example of efficiency
improvement made to a water heat exchanger.)(2) As for technologies of the hot water storage unit side, improvement of thermal insulation
performance by using vacuum thermal insulation materials, etc. is being worked on. (Figure (2)below shows an example of vacuum thermal insulation material.)

(1)

(2)

(Dimple refrigerant tube)(Corrugated water tube)<Water heat exchanger>
Pressure loss of refrigerant isreduced by taking advantageof the shape of refrigerant
tubes and water tubes.
Meanwhile, heat exchange
efficiency is improved byexpanding the heat exchange
area.

(Vacuum thermal
insulation material)<Vacuum thermal insulationmaterial>
Efficiency is improved byadopting vacuum thermal
insulation materials whose
thermal insulation
performance is better thanthose of conventional glass
wool or foamed polystyrene.

8Attachment
Methods for Measurement and Calculation of Annual Efficiency of Water Heating’s
Heat-retention (for Products with a Heat-retention Function)

1. Procedures for measurement and calculation of annual efficiency of water heating’s
heat-retention
A residential heat pump water heater is composed of a “heat pump unit” and a “hot water
storage unit”.
Heat pump unit
Electricity

Hot water
storage unit

Compressor

Kitchen
Hot water supply

Refrigerant
cycle

Expansion
valve

Wash room

Water
heatingHeat takenfrom air

Air heatexchanger

Water heatexchanger

Bath

Pump

Water supply

Composition of residential heat pump water heater● Specific procedures for the measurement and calculation of the energy consumption efficiency
are as follows.
[Procedure (1)] Calculation of “efficiency of water heating’s
heat-retention mode” of a system as a whole- The measurement is performed under the “water heating’s heat-retention mode (winterconditions)” considering actual usage conditions.

[Procedure (2)] Calculation of “heat pump unit’s single unit efficiency”- The measurement is performed under 6 temperature conditions (i.e. standard heating
conditions (middle season, summer and winter), high temperature heating conditions(winter and frosting season) and water heating mode’s heating conditions).
* As regards the specifications for cold areas, the measurement is additionally performed
under cold area winter’s high temperature heating conditions.

[Procedure (3)] Calculation of “annual efficiency of water heating’s heat-retention”(1) A factor is obtained from the “efficiency of water heating’s heat-retention mode” and the “heatpump unit’s single unit efficiency” under winter conditions, and the “efficiency of water
heating’s heat-retention mode” under each outside temperature is calculated based on thefactor.
(2) The “annual heat amount of water heating’s heat-retention” is calculated from the number ofdays when applicable outside temperature has occurred and the in-coming water temperature.
(3) The “electric energy consumption” is obtained from the “heat amount of water heating’s
heat-retention mode” and the “efficiency of water heating’s heat-retention mode” under eachoutside temperature, and the “annual electric energy consumption” is calculated from the their
total.
(4) The “annual efficiency of water heating’s heat-retention” is calculated from the “annual heatamount of water heating’s heat-retention” and the “annual electric energy consumption”.

12. Outline of methods for the measurement and calculation of annual efficiency of water
heating’s heat-retention
Temperature
condition

Items

Outline - In case of products with a bath heat-retention function Air temperature: Dry bulb 7.0±1°C, wet bulb 6.0±0.5°C
Water temperature: Water supply temperature 9.0±2.0°C
Placement of test equipment and measurement instruments of a heat pump water heater (Example)

Heat
pump
unit

Flow meter
Temperature gauge

BathTest room air conditioner

Return from HP
Go to HP
Water supply
Hot water supply
Go to bath
Return from bath

Water supply
unit

Test equipment
Operation state
Water heating
heat-retention’sheat amount

Test method

Procedure (1) Calculation of “efficiency of water heating heat-retention mode”

Hot water
storage unit

Measurement instrumentsa) The temperature gauge for the measurement of water supply temperature and hot water supply temperatureand the flow meter for the measurement of hot water supply amountb) The temperature gauge for the measurement of going-to-bath temperature and returning-from-bathtemperature and the flow meter for the measurement of hot water amountc) The integrating watt meter for the measurement of electric power consumption of a residential heat pumpwater heaterd) The temperature gauge and the flow meter for the measurement of incoming water temperature and outgoing
hot water temperature of the heat pumpe) The thermocouple for the confirmation of the heat amount of the hot water remaining in the hot water storagetank.
The test is conducted by operating a residential heat pump water heater under the rated frequency and the rated
voltage (the tolerance must be within ±2% of each rating).
The residential heat pump water heater is operated with the operational setting preset at the time of shipment.
However, in case of a product equipped with a learning control function, it is operated with the operational setting
preset at the time of shipment until the operation is stabilized under the water heating’s heat-retention mode. If
remaining hot water amount after the operation is stabilized is below 100 L, when converted to that of 40°C, the test
operation setting must be that which makes the remaining hot water amount 100 L or above, when converted tothat of 40°C. The method for setting this test operation must be described in technical data. The heating-up
temperature in the test operation setting must be the heating-up temperature appearing when the operation isstabilized under the water heating’s heat-retention mode operated with the operational setting preset at the time of
shipment or above that.
Water heating’s heat-retention mode: “Water heating’s standard usage mode of bathtubs with a water heater” of JIS
S 2072 is adopted (Attachment 1).
* To enhance the accuracy of the measurement of the water heating’s heat amount, a mode integrating
continuous use is set (Attachment 2).
(As the hot water supply mode, the “standard usage mode of hot water supply equipment used in kitchens, washingrooms, showers and baths” of TS S 0003 is adopted.)
The test of the hot water supply mode’s performance is conducted with the following schedule, and the heat amountof water heating’s heat-retention and the electric energy consumption on the third day are measured. The water
heating’s heat amount of each day must be within the range of ±5%, and the heating-up’s heat amount on the second
and third days must be within the range of ±5%.
<Presumed time>
7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 0 1 2 3 4 5 6(1)(2)

Heating-up
Water heating, heat-retention

Water heating, heat-retention
(3)

(4)

Water heating, heat-retention
Time zone for measuring
heating-up's heat amount

2

Time zone for measuring
electric energy consumption

ItemsOutline - In case of products with a bath heat-retention function The efficiency of water heating’s heat-retention mode is calculated by the following formula.

CMW1

QMW1
PMW1 3.6

Here:
CMW1: Efficiency of water heating’s heat-retention mode
QMW1: Heat amount of water heating’s heat-retention mode (MJ) <- Total of water heating’s heat amount andheat-retention’s heat amount of one day
PMW1: Electric energy consumption of water heating’s heat-retention mode (kWh) <- Electric energy
consumption of one day when operating under water heating's heat-retention mode
3.6:
Factor for converting kWh to MJ
Water heating’s heat amount

Q

te
j ts

Calculation formula

Procedure (1) Calculation of “efficiency of water heating heat-retention mode” of the system as a whole

Efficiency of water heating’s heat-retention mode

Here:
Q:
j:
Tm :
ts :
te :
Ti :
ρ:
cp:
qm:
tm :

Tm Ti

qm

c p tmHeat amount of each water heating mode (kJ)Classification numbered for each measurement interval
Water heating temperature (°C)
Time when hot water supply starts
Time when hot water supply ends
Water supply temperature when simultaneously measuring each hot water supply temperature (°C)
Water density at each hot water supply temperature (kg/L)……(from Table A.4)
Average specific heat of water 4.1796 (kJ/kg･°C)……(constant value)
Flow rate in measurement interval (L/min)
Measurement interval (min)Heat-retention’s heat amount

Qｋ

te
j ts

Tok

Tik

qｋ

c p tｋHere:
Q k: Heat amount of each heat-retention mode (kJ)j:Classification numbered for each measurement interval
ToK: Going-to-bath temperature (°C)
ts: Time when valid water heating’s heat amount starts
te: Time when hot water supply ends
Tik: Returning-from-bath temperature when simultaneously measuring going-to-bath temperature (°C)ρ:
Water density at going-to-bath temperature (kg/L)…… (from Table A.4)
cp: Average specific heat of water 4.1796 (kJ/kg･°C)…… (constant value)
qk: Flow rate in measurement interval (L/min)tm: Measurement interval (min)Integration is made when ToK > Tik condition is met.

3

ItemsOutline - In case of products with a bath heat-retention function Unit: °C
Setting of hot watertemperature

Temperature conditions

Conditions
Middle season standard
heating condition
Summer standard
heating condition
Winter standard heating
condition
Winter high temperature
heating condition
Frosting season hightemperature heating
condition
Cold area winter hightemperature heating
condition
Water heating modeheating condition

Dry bulb
Wet bulb
temperature temperatureStandard heating-up
temperatureStandard heating-up
temperatureStandard heating-up
temperature
Winter high temperature
heating-up temperature
Frosting season hightemperature heating-up
temperature
Cold area winter hightemperature heating-up
temperature
Heating-up temperature at thetime of water heating mode
performance test

Water
temperature
In-coming watertemperature

Procedure (3)COP performanceline No.

16

12

17

(2)

25

21

24

(3)

7

6

9

(1)

7

6

9

(4)

2

1

5

(5)

–7

–8

5

(6)

7

6

9

(8)

* The performance test under the cold area winter high temperature heating condition is implemented for productswith cold area specifications.

Flow meter

Test method

Water supply
unit

Temperature gauge
Heat
pump
unit

Test room air conditioner

Test equipment

Placement of test equipment (Example)a) Measurement under steady condition
The measurement is implemented 7 times at 5 minute intervals after operating the unit for 1 hour or more after
the test condition reaches steady condition.
b) Measurement under transient condition
A heating capacity test for heat pumps in a frosty area.
The “heat pump unit’s single unit efficiency” under each condition is calculated by dividing the heating capacity
calculated with the following method by the electric power consumption at the time of steady condition. The
heating capacity is calculated by the following formula, using the average of measured values.

Calculation formula

Procedure (2) Calculation of “heat pump unit’s single unit efficiency”

Inlet air temperatureΦ(T2T1 )・qr・c p

Here: Φ: Total heating capacity of a heat pump calculated from the heat exchange amount of the heat exchanger ofthe use side.
T1: Water temperature at the inlet of the heat exchanger of the use side (°C)
T2: Water temperature at the outlet of the heat exchanger of the use side (°C)
cp: Specific heat of water (J/kg°C)
qr: Mass flow rate of the heat exchanger of the use side (kg/s)=> The energy consumption efficiency of water heating’s heat-retention mode CHMT1 is the “heat pump unit’s single
unit efficiency” under the heating-up temperature at the time of the performance test of the water heating
mode.

4

ItemsOutline - In case of products with a bath heat-retention function -Water heating’s heat-retention

efficiency factor of a heat pumpenergy consumption efficiency of water heating’s heat-retention mode CHMT1 calculated in the procedure (2). The
water heating’s heat-retention efficiency factor FHM1 of a heat pump is calculated by the following formula.

FHM1
Here:

C MW1
C HMT1

CHMT1: Energy consumption efficiency of water heating’s heat-retention mode

← From the procedure (2)CMW1: Efficiency of water heating’s heat-retention mode

← From the procedure (1)Number of days when the listed average outside nighttime temperature has occurred in a year.
Temperature
Outsidecategorytemperaturejtj°C

Temperature condition

Procedure (3) Calculation of “annual efficiency of water heating’s heat-retention”

The ratio between the efficiency of water heating’s heat-retention mode CMW1 calculated in the procedure (1) and the

Number of Temperature
Outsidedays
categorytemperature
dj
j
tj
d
°C

Number of Temperature
Outsidedays
categorytemperature
dj
j
tj
d
°C

Number of
days
dj
d

1

–10

0

16

5

17

31

20

15

2

–9

0

17

6

17

32

21

15

3
4

–8
–7

0
0

18
19

7
8

15
15

33
34

22
23

13
14

5

–6

0

20

9

13

35

24

11

6

–5

0

21

10

12

36

25

12

7
8

–4
–3

0
0

22
23

11
12

11
12

37
38

26
27

13
14

9

–2

0

24

13

10

39

28

15

10

–1

0

25

14

12

40

29

7

11
12

0
1

1
1

26
27

15
16

13
13

41
42

30
31

2
0

13

2

5

28

17

14

43

32

0

14

3

9

29

18

15

–

–

15

4

15

30

19

14

5

Total

–
365

ItemsOutline - In case of products with a bath heat-retention function From the heat pump unit’s single unit
efficiency(COP)

measured

under

each

3
2

the heat pump unit's single unit efficiency

65℃ 10ＣＯＰ(COP) under each outside temperature andeach hot water temperature is calculated(Right figure: COP performance line).

70℃ 11

14

13

heat pump’s single unit efficiency under eachoutside temperature and each hot water
6
14

temperature, the efficiency of water heating’s

8

5
13

16

15
3
75℃

9

II) From the water heating’s heat-retention
efficiency factor FHM1 of a heat pump and the

1

2

12
8
11 4

90℃

7
12

heat-retention mode CM1 (tj) under eachoutside temperature is calculated (Right-7

figure: Efficiency performance line of water

2

5.5 7

16
外気温度
Outside temperature25

給湯保温モード効率

condition as described in the procedure (2),Efficiency of water heating’s heat-retention modeI)heating’s heat-retention mode).
III) The annual heat amount of water heating’s heat-retention QMA1 is calculated by multiplying the heat amountof water heating’s heat-retention QM1 (tj) under outside temperature tj by the number of days when the outside
temperature was tj, then by totaling them.
43

QMA1＝

QM1 (tj )・dj

Calculation formula

j＝1

outsidetemperaturetj

iscalculatedbydividing the heat amount of water heating’s
heat-retention QM1 (tj) under the outside
temperature tj by the efficiency of water
heating’s heat-retention mode CM1 (tj), and theannual electric energy consumption PMA1 ofwater

heating’s

heat-retention

mode

Water temperature (°C)

IV) The electric energy consumption PM1 (tj) under
Hot water supply temperature(Washing room, kitchen, bath, shower)

Water supply
temperature (°C)

isconsumption calculated above by the numberof days when outside temperature was tj, thenby totaling them.
43

PMA1
j 1

QM1 (tj )djC M1 (tj ) 3.6

Number of days (d)calculated by multiplying the electric energyV) The annual efficiency of water heating’s
heat-retention CMA1 is calculatedbyOutside temperature tj (°C)

thefollowing formula.

CMA1
Here:
CMA1:

QMA1
PMA1 3.6

Annual efficiency of water heating’s heat-retention when performing water heating’s heat-retention under
Annual heat amount of water heating’s heat-retention mode (MJ)

PMA1:

Annual electric energy consumption of water heating’s heat-retention mode (kWh)3.6:

Factor for converting kWh to MJ

To be evaluated by changing the load of water heating’s heat-retention to the water heating’s heat-retention mode
members

For householdswith only a few

Otherswater heating’s heat-retention mode
QMA1:

for households with only a few members (stipulation).
* A mode integrating the water heating's heat-retention mode for a few people and the actions for continuing sameuse is created (Attachment 3).

6

ItemsOutline - In case of products with a bath heat-retention function The annual efficiency of water heating’s heat-retention is calculated by replacing the foregoing numbers of theoutside temperature, water supply temperature and number of days with the following numbers.

The annual

efficiency of water heating’s heat-retention is indicated too for reference.
II Area (Morioka)

Specifications for cold areas

Temperature
OutsideCategory temperature
j
tj
°C
1
–10

Number of Temperature
Outsidedays
Category temperature
dj
j
tj
d
°C
0
16
5

Number of Temperature
Outsidedays
Category temperature
dj
j
tj
d
°C
10
31
20

Number of
days
dj
d
11

2

–9

1

17

6

11

32

21

9

3

–8

2

18

7

11

33

22

9

4
5

–7
–6

3
5

19
20

8
9

9
10

34
35

23
24

9
6

6

–5

8

21

10

9

36

25

4

7

–4

11

22

11

10

37

26

1

8
9

–3
–2

13
15

23
24

12
13

11
11

38
39

27
28

0
0

10

–1

16

25

14

12

40

29

0

11

0

20

26

15

13

41

30

0

12
13

1
2

16
13

27
28

16
17

15
15

42
43

31
32

0
0

14

3

11

29

18

13

–

15

4

9

30

19

13

–

–

Total

365

To calculate the yearly efficiency of water heating’s heat-retention in the specifications for cold areas, heat pumpunit’s single unit efficiency under the following condition is actually measured.
Unit: °C
Condition

Setting of out-going hot
water temperature

Cold area winter highCold area high temperaturetemperature heating condition
heating-up temperature

7

Inlet air temperature

Water temperature

Dry bulb
temperature

Wet bulb
temperature

In-coming watertemperature

–7

–8

5

Attachment 1
Water heating and heat-retention mode

Heat quantities are those in the winter condition.

No.

Usage

Start
time

Heat quantity of hot
water heating MJHeat quantity ofheat-retention MJ

Flow rate
L/min

1

Lavatory

7:00:00

1.286

–

5

10.00

2

Lavatory

7:02:30

0.107

–

5

0.83

3

Lavatory

7:03:10

0.107

–

5

0.83

4

Lavatory

7:04:20

0.107

–

5

0.83

5

Lavatory

7:05:00

0.107

–

5

0.83

6

Kitchen

8:15:00

0.643

–

5

5.00

7

Kitchen

8:16:30

0.107

–

5

0.83

8

Kitchen

8:17:10

0.107

–

5

0.83

9

Kitchen

8:27:20

3.214

–

5

25.00

10

Kitchen

8:34:20

0.321

–

5

2.50

11
12
13

Kitchen
Kitchen
Kitchen

13:00:00
13:01:30
13:02:10

0.643
0.107
0.107

–
–
–

5
5
5

5.00
0.83
0.83

14

Kitchen

13:07:20

1.286

–

5

10.00

15

Kitchen

13:10:20

0.321

–

5

2.50

16

Kitchen

18:15:00

0.643

–

5

5.00

17

Kitchen

18:16:30

0.107

–

5

0.83

18

Kitchen

18:18:40

0.643

–

5

5.00

19

Kitchen

18:24:40

0.643

–

5

5.00

20

Kitchen

18:26:10

0.107

–

5

0.83

21

Kitchen

18:26:50

0.107

–

5

0.83

22

Kitchen

18:27:30

0.107

–

5

0.83

23

Kitchen

18:32:40

0.321

–

5

2.50

24

Kitchen

18:33:40

0.107

–

5

0.83

25

Kitchen

18:34:20

0.107

–

5

0.83

26

Bath

19:40:00

23.143–10-15

180.0027

Kitchen

20:00:00

1.286

–

5

10.00

28

Kitchen

20:02:30

0.321

–

5

2.50

29

Shower

20:08:00

2.571

–

10

20.00

30

Kitchen

20:12:00

0.321

–

5

2.50

31

Kitchen

20:13:00

0.107

–

5

0.83

32

Kitchen

20:18:10

0.321

–

5

2.50

33

Kitchen

20:19:10

0.107

–

5

0.83

34

Kitchen

20:19:50

0.107

–

5

0.83

35

Heat-retention

20:27:00

–

1.020

–

–

36

Shower

20:30:00

6.428

–

10

50.00

37

Kitchen

20:36:00

0.107

–

5

0.83

38

Kitchen

20:36:40

0.107

–

5

0.83

39

Kitchen

20:37:20

0.107

–

5

0.83

40

Kitchen

20:38:00

0.107

–

5

0.83

41

Heat-retention

20:57:00

–

0.530

–

–

42

Heat-retention

21:27:00

–

0.530

–

–

43

Heat-retention

21:57:00

–

0.530

–

–

44

Lavatory

22:00:00

1.286

–

5

10.00

45

Lavatory

22:02:30

0.107

–

5

0.83

46

Lavatory

22:03:10

0.107

–

5

0.83

47

Lavatory

22:03:50

0.107

–

5

0.83

48

Shower

22:14:00

2.571

–

10

20.00

49

Lavatory

22:16:30

0.107

–

5

0.83

50

Lavatory

22:17:10

0.107

–

5

0.83

51

Heat-retention

22:27:00

–

1.020

–

–

52

Shower

22:32:20

6.428

–

10

50.00

53

Lavatory

22:39:20

0.321

–

5

2.50

54

Lavatory

22:40:50

0.107

–

5

0.83

55

Lavatory

22:43:00

0.643

–

5

5.00

56

Lavatory

22:45:00

0.107

–

5

0.83

58.5944.120–

455.74Total

Hot water supply
amount L

Attachment 2
Water heating and heat-retention mode
(when operations for the same intended usage are summarized)
Heat quantities are those in the winter condition.
No.

Usage

Start time

Heat quantity of hot
water heating
MJ

Heat quantity ofheat-retention MJ

Flow rate
L/min

Hot water supply
amount L

1

Lavatory

7:00:00

1.713

–

5

13.32

2
3
4

Kitchen
Kitchen
Kitchen

8:25:00
13:05:00
18:25:00

4.392
2.463
2.890

–
–
–

5
5
5

34.16
19.16

5
6
7

Bath
KitchenShower

19:40:00
20:01:00
20:08:00

23.143
1.607
2.571

–
–
–

10-15
5
10

180.0012.50

8
9Kitchen

20:16:00
20:27:00

0.963
–

–
1.020

5
–

7.49
–

22.48

20.00

10

Heat-retention
Shower

20:30:00

6.428

–

10

50.00

11

Kitchen

20:37:00

0.427

–

5

3.32

12
13

Heat-retention

–
–

1.020
0.530

–
–

–

Heat-retention

20:57:00
21:27:00

14
15
16

Heat-retention
Lavatory
Shower

21:57:00
22:02:00
22:14:00

–
1.606
2.571

0.530
–
–

–
5
10

–
12.49

17
18
19

Lavatory

22:17:00
22:27:00
22:32:20

0.213
–
6.428

–
1.020
–

5
–
10

1.66
–
50.00

22:43:00

1.178
58.594

–
4.120

5
–

9.16
455.7420

Heat-retention
ShowerLavatory
Total

–

20.00

Attachment 3
Water heating and heat-retention mode for household with fewer family members
Heat quantities are those in the winter condition.
No.

Usage

Start
time

1

Lavatory

7:00:00

0.643

–

5

5.00

2

Lavatory

7:02:30

0.107

–

5

0.83

3

Lavatory

7:03:10

0.107

–

5

0.83

4

Kitchen

8:15:00

0.129

–

5

1.00

5

Kitchen

8:16:30

0.107

–

5

0.83

6

Kitchen

8:17:10

0.107

–

5

0.83

7

Kitchen

8:27:20

1.286

–

5

10.00

8

Kitchen

8:34:20

0.129

–

5

1.00

9

Kitchen

13:00:00

0.129

–

5

1.00

10

Kitchen

13:01:30

0.107

–

5

0.83

11

Kitchen

13:02:10

0.107

–

5

0.83

12

Kitchen

13:07:20

0.514

–

5

4.00

13

Kitchen

13:10:20

0.129

–

5

1.00

14

Kitchen

18:15:00

0.193

–

5

1.50

15

Kitchen

18:16:30

0.107

–

5

0.83

16

Kitchen

18:18:40

0.257

–

5

2.00

17

Kitchen

18:24:40

0.172

–

5

1.34

18

Kitchen

18:26:50

0.107

–

5

0.83

19

Kitchen

18:27:30

0.107

–

5

0.83

20

Kitchen

18:32:40

0.214

–

5

1.66

21

Kitchen

20:00:00

0.514

–

5

4.00

22

Kitchen

20:02:30

0.129

–

5

1.00

23

Kitchen

20:12:00

0.171

–

5

1.33

24

Kitchen

20:18:10

0.214

–

5

1.66

25

Kitchen

20:37:00

0.171

–

5

1.33

26

Bath

20:40:00

19.285–10-15

150.0027

Shower

21:08:00

2.571

–

10

20.00

28

Heat-retention

21:27:00

–

0.850

–

–

29

Heat-retention

21:57:00

–

0.442

–

–

30

Heat-retention

22:27:00

–

0.442

–

–

31

Shower

22:32:20

6.428

–

10

50.00

32

Lavatory

22:39:20

0.910

–

5

7.08

33

Lavatory

22:42:00

0.214

–

5

1.67

34

Lavatory

22:44:30

0.375

–

5

2.92

35.7371.734–

277.96

Total

Heat quantity of hot
water heating
MJ

Heat quantity ofheat-retention MJ

Flow rate
L/min

Hot water supply
amount L

Water heating and heat-retention mode for household with fewer family members (whenoperations for the same intended usage are summarized)

Heat quantities are those in the winter condition.

No.

Usage

Start
time

Heat quantity of hot
water heating
MJ

Heat quantity ofheat-retention MJ

Flow rate
L/min

Hot water supply
amount L

1

Lavatory

7:00:00

0.856

–

5

6.66

2

Kitchen

8:25:00

1.757

–

5

13.66

3

Kitchen

13:05:00

0.985

–

5

7.66

4

Kitchen

18:25:00

1.156

–

5

8.99

5

Kitchen

20:01:00

0.643

–

5

5.00

6

Kitchen

20:16:00

0.385

–

5

3 00

7

Kitchen

20:37:00

0.171

–

5

1.33

8

Bath

20:40:00

19.285–10-15

150.009

Shower

21:08:00

2.571

–

10

20.00

10

Heat-retention

21:27:00

–

0.850

–

–

11

Heat-retention

21:57:00

–

0.442

–

–

12

Heat-retention

22:27:00

–

0.442

–

–

13

Shower

22:32:20

6.428

–

10

50.00

14

Lavatory

22:43:00

1.498

–

5

11.66

35.7371.734–

277.96

Total

Attachment 6
Heat Pump Water Heater Evaluation Standards Subcommittee,
Energy Efficiency Standards Subcommittee of the Advisory Committee
for Natural Resources and Energy
Meeting History

First Subcommittee Meeting (July 20, 2010)- Disclosure of the Heat Pump Water Heater Evaluation Standards Subcommittee- Current status of heat pump water heaters- Scope of heat pump water heaters- Energy consumption efficiency of heat pump water heaters and its measurement
methodSecond Subcommittee Meeting (March 28, 2012)- Classification of heat pump water heaters- Target fiscal year and target standard values for heat pump water heaters

Third Subcommittee Meeting (April 17, 2012)- Interim report on heat pump water heaters

Attachment 7

Heat Pump Water Heater Evaluation Standards Subcommittee,
Energy Efficiency Standards Subcommittee of the Advisory Committee
for Natural Resources and Energy
List of Members
Chairman

Motoyasu Kamata

Professor Emeritus, The University of Tokyo

Members

Yukie Iino

Researcher, Consumer Lives Research Center,
Japan Consumer’s Association

Tadayoshi Tanaka

General Manager, Technology Planning andManagement Department, The Energy
Conservation Center, Japan(Replaced by committee member Inoue from thesecond meeting)Mamoru Inoue

General Manager, Technology Planning andManagement Department, The Energy
Conservation Center, Japan(Joined from the second meeting)

Shinya Okada

Deputy Chairman, Heat Pump Water Heater
Committee, The Japan Refrigeration and Air
Conditioning Industry Association

Kiyoshi Saito

Professor, Faculty of Science and Engineering,
Waseda University

Masako Sugimoto

Director, Nippon Association of Consumer
Specialists

Hirofumi Daiguji

Associate Professor, Graduate School of Frontier
Sciences, The University of Tokyo

Koichi Takubo

Manager, Business Department, The Federation ofElectric Power Companies of Japan

Chiharu Murakoshi Vice President, Jyukankyo Research Institute Inc.

Reference

Status Quo of Heat Pump Water
Heaters
July 22, 2010
Ministry of Economy, Trade and Industry
Commerce and Information Policy Bureau
Information and Communication
Electronics Division11. What is Heat Pump Water Heater?
Heat pump water heaters
A collective name for water heaters using the principle of heat pump as in the case of air
conditioners. They are considered as products excellent in energy saving performance. There areresidential heat pump water heaters and commercial heat pump water heaters.

* The name “EcoCute” is a registered trade name of the Kansai Electric Power Co.,
Inc., which is used by many companies with the permission of said company.

Features

The heat pump unit ((1) in the right figure) efficiently
makes a large amount of hot water, and then it is stored(storage temperature at 65 to 90℃) in the hot water storage
unit ((2) in the right figure). Hot water is served from thestorage unit when it is used at baths, lavatories, kitchens,etc.
Residential heat pump water heaters generally make hotwater using less expensive nighttime electricity, so theirelectric bill is relatively low.

(2) Hot water
storage unit

Refrigerant used

Heat pump water heaters using HFC (fluorocarbon) as
refrigerant are conventionally available in the market.
However, those using carbon dioxide (CO2) as refrigerant
were developed in 2001, and the demands, especially forresidential models, has been expanding. (Somecommercial models are still using HFC.)(1) Heat pumpunit
2

2. Types of Heat Pump Water Heaters (1)Residential heat pump water heaters
Residential heat pump water heaters are classified into several types according to their tankshape, capacity, function, etc. The capacity ranges from 370 to 460 L in case of products forstandard households (4 family members) and from 150 to 200 L in case of compact tanks (for asingle, 2 family members, etc.).

1. Types by tank shape and capacity<Standard tank><Thin tank><Compact tank><All-in-one type>

2. Types by function
a. Full-auto type
Those equipped with functions of “automatic hot water filling”, “hot water adding”,“automatic heat-retention” and “reheating” for bath.
b. Auto (semi-auto) type
Those equipped with functions of “automatic hot water filling” and “hot water adding” for bath.
c. Hot water supply only type
Those designed only for hot water supply, so they fill a bath with hot water through a faucet.
d. Multifunction type
Those equipped with a floor heating function in addition to a hot water supply function forbath, lavatory, kitchen, etc.
3

3. Types of Heat Pump Water Heaters (2)Commercial heat pump water heaters
Commercial heat pump water heaters are used in commercial facilities such asbuildings, hotels, etc. Following types are available according to their scales and hot
water amount used.
<For small scale buildings>
Clinics, inns,
small welfare facilities, etc.
Restaurants, shops, etc.

<For large scale buildings>
Hospitals, hotels, large welfare
facilities
Sports spa facilities,
meal supply facilities, etc.

4

4. Shipping Quantity of Heat Pump Water Heaters (1)(Residential)
Residential heat pump water heaters
Shipping quantity of residential heat pump water heaters started to rapidly increase in aroundyear 2002 (*), making cumulative shipping quantity reach approximately 2.25 million units.
Shipment quantity in FY2009 is 508 thousand units, and the market size remains at around 500
thousand units likewise in the previous year.
Main manufacturers are the following 12 companies, and there are few imported products soldin the market.
* A “subsidy system” in which the government bears part of the cost to install heat pump water heaters(CO2 refrigerant) was implemented in FY2002. Since then, thanks to this subsidy system in part, thenumber of installed units has rapidly increased.

Main manufacturers of residential products
Corona Corporation
Sanden Corporation
SANYO Electric Co., Ltd.
Daikin Industries, Ltd.
Choshu Industry Co., Ltd.
CHOFU SEISAKUSHO Co., Ltd.
DENSO Corporation
TOSHIBA CARRIER Corporation
Housetec Inc.
Panasonic Corporation
Hitachi Appliances, Inc.
Mitsubishi Electric Corporation(In Japanese alphabetical order)

Transition of shipping quantity ofresidential models (Unit: One thousand units)

600

500 508

500

413

400

350

300

226

200
100
0

3 37

81

131

2001 2002 2003 2004 2005 2006 2007 2008 2009
Data provided by The Japan Refrigeration and Air
Conditioning Industry Association

55. Shipping Quantity of Heat Pump Water Heaters (2)(Commercial)Commercial Heat Pump Water Heaters
Shipping quantity of commercial heat pump water heaters in FY2009 is 3.6
thousand units, and its cumulative shipping quantity is 10 thousand plus units. Its
market size is small compared with that of residential models, occupying only lessthan 1% of the heat pump water heater market as a whole.
Main manufacturers are the following companies, and there are few imported
products.
● Transition of shipping quantity,commercial (Unit: One thousand units)● Main manufacturers of commercial products

Showa Manufacturing Co., Ltd.
Daikin Industries, Ltd.
DENSO Corporation
TOSHIBA CARRIER Corporation
Nihon Itomic Co., Ltd.
Panasonic Corporation
Hitachi Appliances, Inc.
MAYEKAWA MFG. Co., Ltd.
Mitsubishi Electric Corporation(In Japanese alphabetical order)

60
50
40
30
20
10
0

1.6 2.2 3.5 3.6
2001 2002 2003 2004 2005 2006 2007 2008 2009
Data provided by The Japan Refrigeration
and Air Conditioning Industry Association

66. Technology of Heat Pump Water Heaters (1)Principle of making hot water
Using the “principle of heat pump” which is also employed in air conditioners, heat pump water
heaters make hot water through the compression-expansion cycle of refrigerant, store it in a hotwater storage tank and supply it.
(1) A heat pump water heater makes its refrigerant to absorb heat from air through an “air heatexchanger” and compresses the refrigerant with a compressor to bring it into a high temperatureand high pressure state. (2) Then, the heat of the refrigerant is transferred to water through a“water heat exchanger”, and the produced hot water is stored in a hot water storage tank. (3)The refrigerant which lost heat is expanded by an expansion valve to bring it back to a lowtemperature and low pressure state again in which it can easily absorb heat from air. A heatpump water heater is a mechanism repeating this procedure.
* Hot water stored in the hot water storage
unit is kept hot and used according to the
purpose of use.

•In a heat pump unit, hotwater is made throughheat exchange using theheat of air.

Heat pump unit

Air heatexchanger(3)

KitchenCompressor(1)
Absorptionof hear fromair

Hot water supply

Water
heat
exchanger(2)
Refrigerant
cycle

Expansionvalve

Lavatory

Waterheating

Electricity

Hot water
storage unit

Bath

Pump

Water
supply7

7. Technology of Heat Pump Water Heaters (2)Toward further energy saving
To realize further energy saving, efficiency of every component is being enhanced.
(1) As for technologies of the heat pump side, efficiency improvement of heat exchangers,
compressors, etc. is being worked on. (Figure (1) below shows an example of efficiency
improvement made to a water heat exchanger.)(2) As for technologies of the hot water storage unit side, improvement of thermal insulation
performance by using vacuum thermal insulation materials, etc. is being worked on. (Figure (2)below shows an example of vacuum thermal insulation material.)

(1)

(2)

(Dimple refrigerant tube)(Corrugated water tube)<Water heat exchanger>
Pressure loss of refrigerant isreduced by taking advantageof the shape of refrigerant
tubes and water tubes.
Meanwhile, heat exchange
efficiency is improved byexpanding the heat exchange
area.

(Vacuum thermal
insulation material)<Vacuum thermal insulationmaterial>
Efficiency is improved byadopting vacuum thermal
insulation materials whose
thermal insulation
performance is better thanthose of conventional glass
wool or foamed polystyrene.

8