                                 May, 2017, Vol.8

AHPNW
NEWSLETTERCONTENTS~Related News~1.
New government - New energy policy
2.
3.

China Refrigeration Expo Opening- 2016 Energy Conservation Prize Ceremony at ENEX 2017
- The current situation of full Liberalization of the Power Retailing Business- Full Liberalization of the City Gas Retailing Business-‘Energy management by using Thermal Storage Air-conditioning System’
has published. - From a plan and a design to an operation –~Research Papers~
4.
5.

Application Analyse of a Ground Source Heat Pump System in a Nearly Zero
Energy Building in China
Load Variations with Seasonal Conditions Affected to Coefficient of
Performance of Air to Water Heat Pump

Related News

From Korea‫ ڦ‬New government - New energy
policyIt is noteworthy how President Moon's
realization of the energy policy promisepresented during the presidential election
will be realized. The key to President
Moon's energy policy pledge is to increase
the LNG and renewable power generation
instead of lowering the nuclear power plantand coal-fired power considered maincause of fine dust occurred.
Firstly the government proposed to suspend
the construction of Shin Gori 5 and 6,
extend the life of Wolseong 1, andreexamine the entire plan for construction of
new nuclear power plants. For old-age
nuclear power plants, they should be
strengthened with seismic capacity of 6.5 orhigher and nuclear power plant is not able
to enhance with seismic performance
should be shut down in sequence, and theextension of the life span of Wolseong
Nuclear Power Plant 2, 3 and 4 is strictly
restricted. It also decided to curb theconstruction of a new coal-fired power plant.
It is time to reexamine the construction ofnine coal-fired power plants. It aims to raise
the utilization rate of LNG power generationfrom 20% to 60%, and to achieve 20% of
renewable energy generation by 2030
mainly with solar and wind power.
President Moon is expected to curb nuclear
power plants and coal-fired power plants,
but it is unlikely that it will be easy to cancel
plans for construction of nuclear power
plants and coal-fired power plants that havealready been decided. If the proportion of
LNG and renewable energy is relatively
high instead of reducing nuclear power
plants and coal-fired power generation
costs that are low in power generation costs,
it is inevitable to raise electricity costs due
to rising costs. The national consensus is a
big challenge. Mr. Moon thinks that he will

reduce the burden on consumers by
improving efficiency and strengthening
demand management. Although the LNG
industry is expected to see a positive
impact on the sales of private LNG
producers, it is welcomed, but it is a difficult
task for the government. The Ministry ofIndustry and Energy has pointed out that itis necessary to enlarge the proportion of
LNG
power
generation
toreducegreenhouse gas emissions. In addition toenvironmental protection, it is necessary tobalance various aspects such as economic
efficiency and energy security. LNG power
generation contributes to greenhouse gas
reduction compared to coal, but it isdisadvantageous compared to nuclear
power plants. In North America and Europe,
it is possible to use relatively cheap power
generation costs by using shale gas or PNG
as a fuel. However, we believe that it isdesirable to operate with the peak demandbecause the cost of introducing LNG is high.
President Moon is planning to reorganize
the energy price system for energy supply
considering safety and environment. And it
is to improve the taxation system for power
generation fuels. Also, it is expected thatthe new and renewable energy industry will
be revitalized, but there are many obstacles
to be overcome such as deregulation of thedowntown area. It is noteworthy that policychanges such as the improvement of the
RPS system and the re-introduction of the
FIT system will take place by expanding the
proportion of renewable energy, mainly
solar and wind power. It is suggested thattechnological progress is necessary toutilize the electricity generated by solar
power and wind power as well as to utilize
remaining electricity to charge electricvehicles.
President Moon also expressed his
intention to broaden the distributed power
supply and encourage the integrated
energy supply. An expert in the industry
said, "The promise to expand the integrated
energy supply as a core business of theRelated News
distributed power supply is not only one-off,but it must be fostered in the long run." In
the light of the reduction of nuclear power
plants and coal-fired power, I look forward
to it. "President Moon said that the current
government organization is limiting thechange of energy policy and that he isconsidering the creation of the Energy
Independent Ministry (Climate Energy
Department).
(Source : 12 May 2017,
Today Energy Magazine)

From China‫ڦ‬China Refrigeration Expo Opening
April 12, 2017, China Refrigeration Expo
opened in Shanghai.
Exhibitors were from 33 countries andregions, more than 1,200 enterprises andinstitutions. The total exhibition area was
about 103,500 square meters, net area wasclose to 50,000 square meters.
The exhibition attracted the attention of theworld's refrigeration HVAC industry, thevast majority of well-known brands. Morethan 100 countries and regions, more than
60,000 professional visitors and users cameto visit and negotiate cooperation.
The theme of the exhibition was ingenuity,
intellectual creation, tolerance, sharing.
Around these theme, the organizers
organized a wide range of exchange
activities during the exhibition, including thecomprehensive analysis of national policies,
the industry hot spots, technologicalinnovation and future development of thegeneraldirectiontopromotethedevelopment of green exhibition concept, tofulfill the sponsor's social responsibility
during the exhibition.
(Source:http://www.cr-expo.com)

From Japan‫ڦ‬2016 Energy Conservation Prize
Ceremony at ENEX 2017
On February 15, on the occasion of
ENEX2017, the Energy Conservation Prize
Commendation
Ceremony
was
performed.
Thiscommendation program is intended tocommend excellent attempts atenergy saving, products and businessmodels having high energy performance
made or developed bymanufacturers or organizations that canserve as a model for others. The prize isorganized by the
Energy Conservation Center, Japan (ECCJ)
and aims to contribute to the expansion ofnationwide
awareness of the need for energy
conservation and to create an energy
conservation-oriented society
by dispatching the necessary information
and accelerating PR through publicly
announcing the resultsof screening and prize winners, while
showing all application examples andoutlines of prize-winning products.
JARN
introduces
theprize-winningcompanies in the Product/ Business Model
Category.
Panasonic received the Minister Prize of
Economic, Trade and Industry in the
Product (Home) Segment for its
WX series room air conditioners (RACs)
incorporating a double temperature andsimultaneously/ selectively
discharging airstream system.
Daikin won the Minister Prize of Economic,
Trade and Industry in the Product(Commercial) Segment for its
Retrofit System for existing variablerefrigerant volume (VRV) systems.
Moreover, Mitsubishi Heavy Industries
Thermal Systems (MTH) was awarded the
Director General Prize of Agency

Related Newsof Natural Resources and Energy in the
Product (Commercial) Segment for its
GART/GARTI series energy saving,large capacity, and compact centrifugal
chillers.
The following companies are the Chairman
Prize of ECCJ winners. Daikin for its
residential multi-split air conditioner
that can be connected to a floor heating
system; Mitsubishi Electric for its Mr. Slim
ZR series type P280 packaged
air conditioners (PACs) for store/office use;
Panasonic Ecology Systems for its
residential heat exchanging system
incorporating an IAQ Control function;
Johnson Controls-Hitachi Air conditioning(JCH) for its Flexmulti high efficiency
heat pump type variable refrigerant flow(VRF) systems for building air conditioning;
JCH for its Stainless Clean
Shirokumakun X series RACs; Toshiba
Carrier and Chubu Electric Power for their
Super Power Eco Gold P224 andP280 air conditioners for store/office use;
Toshiba Lifestyle Products and Services for
its Magic large capacity seriesenergy saving freezer-refrigerators; Coronaand Denso for their Corona Premium Eco
Cute heat pump water heater
adopting CO2 refrigerant;and Rinnai for its
Eco One residential hybrid water heating
apace heating system.
(source : 2017/3/25,JARN)‫ ڦ‬Thecurrent situation of full
Liberalization of the Power Retailing
Business

On April 1, 2016, the power retailingbusiness was fully liberalized, and all
consumers including ordinary households
and stores are now able to freely selectpower
suppliers
andelectric
rate
systems.The size of the newly liberalized
electricity market is worth approximately 8
trillion yen annually. Competition caused by
new entries from other business sectors isbringing about benefits to consumers suchas a restraining effect on price increases
and provision of new services.

As of 6th April 2017, about 390 retailers
were registered and approximately 181,000
customers has switched their power
suppliers. So newly established powercompany's share is now 3% in low voltage
customers market and also 8% in total
electrical power market.Innovation basedon diverse consumer needs will create
dynamic power-related markets and generalenergy companies targeting overseas
markets may emerge in the future.
(Source; Japan, METI homepage etc.)‫ ڦ‬Full Liberalization of the City Gas
Retailing Business
On April 1, 2017, the gas retailing business
was fully liberalized. To the commercial big
users, the market was liberalized from1955.So the two third of the total Gas
retailing market has liberalized and about
30 companies are entered this business.
However, ‘Security Obligation’ is one of the
big entry barrier, so the new entry
companies are very limited, compared with
the Power Retailing liberalization.
*Security Obligation : New company needs
to prepare personels who can check the
security matters(Source; Japan, METI homepage etc.)‫’ ڦ‬Energy management by using
ThermalStorage
Air-conditioning
System’ has published.
- From a plan and a design to an
operation –Contents
1.Whatthethermalstorageairconditioning system is
2.Energy management by TES
3.The main point on the plan of a thermal
storage type air-conditioning system
4.The design of a thermal storage type airconditioning system
5.The design of a heat storage tank, andconstruction of a thermal storage typeair-conditioning system

Research Paper
Related News
6.Operation and the maintenance/control
of a thermal storage type air-conditioning
system
7.The case study of the energy
management by a thermal storage typeair-conditioning system
8.The real application of a thermalstorage
type air-conditioning system*Edit and issue: 2017 March 31 The societyof Heating, Air-Conditioning and SanitaryEngineers of Japan(SHASE)(source : http://www.shasej.org/)

From China

Application Analyse of a Ground Source Heat Pump System in a Nearly Zero
Energy Building in China
Huai Li, Wei Xu, Zhen Yu, Jianlin Wu, Zhifeng Sun
Abstract
Ground source heat pump system has been widely utilized in office buildings in China. Itsapplication in nearly zero energy office building pioneers an innovation in China. This paper
focuses on real operation introduction and performance analysis of a Ground Source Heat
Pump (GSHP) system in a nearly zero energy building (NZEB) with different HVAC terminal
for the first time. The paper introduces the nearly zero energy building with a general
presentation of its energy system, then analyzes GSHP system operation and soil
temperature variation from November 2014 to September 2015 based on real operation data.
The analyses manifests that the HP2# worked under an average COP of about 5.4 and 5.0 insummer and winter, respectively and HP1# worked under an average COP of 3.9 and 3.0 in
winter and summer respectively. In the winter season floor and ceiling radiation system has arelatively higher performance than radiator system due to low supply water temperaturegoing into the room. Room temperature keeps above 20 Υ in the winter season andfluctuated around 26Υ in the summer season. Good room temperature and COP proves the
GSHP system functions excellently. Soil temperature could recover in one year operation.
Keywords: Nearly Zero Energy Building, GSHP system operation, soil temperature
variation, indoor environment comfortable
1.

Introduction
Reducing energy consumption in the building sector is one of the most importantmeasures for global energy reduction and climate adaptation. Nearly/net zero energy
building is one promising path leading to further building energy conservation. Research
regarding design methodologies, technologies, monitoring method or evaluation process et alof nearly zero energy building has been carried out either by researchers or constructors.
Zhihua Zhou et al. [1] published articles regarding operation performance of a “netzero energy building” in China, in which they manifested challenges of nearly zero energy
building development, and gave suggestions for nearly zero energy building to realize design
target in China. Muhammad Waseem Ahmad, et al. [2] focused on available technologies forbuilding energy metering and environment monitoring in nearly zero energy building byanalyzing their advantages and disadvantages. Limei Shen, Xiwang Pu et al [3] presented
the first study on thermoelectric technology applications in NZEB, which shows the system
could satisfy cooling and heating requirement outstandingly, and improves annual solar
generation 767kWh (34%). It provides a progress way to apply thermoelectric technology in
NZEB. ShengZhang [4] proposed a multi-criterion renewable energy system design
optimization method for NZEB under un-certainties, Shicong Zhang[5] introduced theoperation performance of ground source heat pump in CABRNZEB, and analyzed its good
performance in summer season.
China has the biggest GSHP market, and the fastest GSHP yearly application in theworld. Due to high performance and environmental friendly properties, GSHP system has
been recognized as the best choice of energy system of buildings. Researches on groundsource heat pump(GSHP) system goes to two directions, one is numerical simulation work[610], for purposes of proper GSHP design guidance, optimizing system operation especiallyfor a combined system, longer term system operation observation, evaluation of special
types of heat exchanger simulation. The others focus on system application effects, indifferent application environments, control strategies or climate zones [11-20].
A large borehole ground source heat pump system was adopted in a Nearly Zero
Energy Building (NZEB) in Beijing, China. It is a 4-floor office building, with a floor area of
about 4000 m2 and occupancy of approximately 180 full-time employees. Adhering to thedesign principle of "passive building, proactive optimization, economic and pragmatic", theproject integrated cutting-edge building technologies and set up the ambitious annual energy

6Research Paper

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consumption cap of 25 kWh / (m2.a) (including heating, cooling and lighting energy) with anacceptable indoor environment.
This article focuses on performance analysis of a GSHP system in a nearly zeroenergy building with different HVAC terminal through a whole year (2014.11-2015.9) basedon real operational data, including a heating period and a cooling period. Importantparameters such as inlet and outlet water temperatures in the primary and secondary side,
coefficients of performance in summer and winter season, as well as typical days that arepresented to help understanding system performance with different terminal in a low heating
and cooling load building. Suggestions are provided to help optimize GSHP system operation
after real operation data analysis.
2.

Building Introduction
The NZEB integrated cutting-edge building technologies and strived to lay afoundation for China’s NZEB standard. The building adopted prominent thermal insulation to
reduce the cooling and heating energy demands. It uses vacuum insulation board with athermal conductivity of 0.006W/ (m2 K) as insulation. The window has a K value of 1.0 W/(m2 K) which uses vacuum glass and internal electrical shading design. EPS with a thermal
conductivity of 0.03W/ (m2 K) is used in the ceiling. Careful attention has been paid to thedetailed design to avoid the thermal bridge and to maintain good air tightness.
There are different function rooms distributed on each floor. Four floors have almost
the same structures, including office room and meeting rooms, whereas the difference is thescale of the meeting rooms. The meeting room on the first floor could maintain almost 50
people, and the one on the fourth floor is capable of 150 people.

Figure 1 Front view of the nearly zero energy building

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From ChinaFKLOOHU GULYHQ E\ KRW ZDWHU Υ) which was produced by two types of solar collection
systems, processes the ventilation load of the 1st and 4th floor, otherwise (hot watertemperature < 70Υ), a 50kW HP (GSHP1#) will serve the function of absorption chiller
instead, when the switching operation of the two machine unit is controlled by BAS (building
automation system). On the other side, room cooling load of the first floor is provided by(WS-VRV) system, the fourth floor is served by (WS-VRV) and water loop heat pump
(WLHP) system respectively. On the other side, GSHP with 100kW provides ventilation andcooling load of the 2nd and the3rd floor. In the winter season, GSHP1# provides heating andventilation load of the 1st and 4th floor except for the meeting room which was supported by
WLHP if meeting room is in use. The other 100kW GSHP (GSHP 2#) unit is in place to meetheating and ventilation demands from the radiant terminals for the 2nd and the3rd floor.
Performance parameter of the two heat pump is shown in Table 1.
Table 1 Performance parameter of heat pumps

GSHP1

Cooling
Capacity
˄kW˅
50

Power
Input
˄kW˅
9.3

GSHP2

99.5

18.6

HP

5.4

Heating
Capacity
(kW)
51.7

Power
Input
(kW)
13.1

5.3

103.7

25.2

EER

4.

COP
3.9
4.10

Borehole System
Borehole tube is adopted as heat source or heat sink for the system in winter andsummer, and cooling tower is set as an auxiliary cooling system of borehole in summer.
Borehole distribution is illustrated in Fig. 3. Seventy boreholes are placed in open space ofthe demo building boundary, with 20 for double U-tube and 100 meter-depth to the south,and 50 for single U-tube with depth of 60 meters to the north and west. These boreholes aregrouped in 7 sub-loops, where ground water join in a header before entering the building,
and water inside the boreholes exchanges heat with the ground. Since very high temperatureand humidity weather and relatively good U-tube water temperature in summer, cooling
tower is out of use in this system now.
Water in the U-tube has few ways entering the building due to different season andoperation modes, in the summer season, water goes to absorption chiller (if hot water isavailable), HP 1# (if required), HP 2#, VRV system and WLHP units; and in the winterseasons, water goes to GSHP 1#, GSHP 2#, VRV systems and WSHP units if necessary.
Soil temperatures around both single and double borehole tube in different depths ismonitored by PT1000 sensor and operation data are recorded in building energy monitoring
system. PT1000 was calibrated by standard equipment.

3.
Energy System Description
3.1 Energy System
The building serves as an experimental building in several sections, such as
renewable energy application, building envelop, indoor environmental comfort, HAVC
terminals and others.
Solar thermal combined with ground source heat Pump system works as the mainenergy system of this building. As described previously, each floor has office room andmeeting rooms respectively, and considering the demonstration purpose, different heating
and cooling terminal are adopted. Water source variable refrigerant volume (WS-VRV)
system and radiator system are utilized for the first and fourth floor in summer and winterrespectively, whereas the second and third floor employs floor and ceiling radiation systems
respectively.
3.2 Operation strategy
One absorption chiller and two GSHP units are involved in this energy system that are
shown in Figure 2. In summer season when the solar radiation is sufficient, the absorption

Figure 2. Heating and cooling system of the NZEB building

78

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5.1.1 System Operation in Typical Day
GSHP 1#In the winter season, GSHP 1# provides heating and ventilation loads of the 1st and4th floor. Supposedly, if the system operation in the coldest day could satisfy level of theroom temperature comfort, it could meet the heating requirement of the building in the whole
winter season as well.
The system operation in January 27th is analyzed when outside air temperature isabout -7Υ. The system works from around 7:00 am to 17:00 pm as shown in figure 5. Supply(T2out) and return (T2in) water temperatures of the secondary side was approximately 42
and 38Υ respectively, with about 4 degrees difference. Inlet (T1in) and outlet (T1out) watertemperatures on the primary side are about 13 and 9Υ, and the temperature difference isapproximately 4Υ. T1out is found about 0.7Υ temperature decrease after the one-day
operation, which shows the system operated in an interval mode. About 320 kWh heat is
supplied to the building. The hourly average coefficient of performance (COP) is about 3.9 on
average that can be seen from figure 6.
The COP is a measurement of the performance of the system, and it is calculated
from Eq.(1)

COP

Q

(1)

E
Figure 3. Borehole System Distribution

5.
Operation Analyze
5.1 Winter Season Operation
The construction of CABR demo building was finished in May 2014.The test operationof the energy system started from July 1st 2014, when the energy monitoring system was on
operation and progressing elaboration during the first half years. Now the system is under
the second winter operation mode. For complete data analysis, this paper focuses on system
operation from November 2014 to the end of September.2015.
The first winter season operation of the energy system started from 15th November toend of March, Fig. 4 shows outside air temperature variation during this period, which varies
from -7 to 5Υ. It was a relatively warm winter.
GSHP system operation in a typical day is analyzed first and the system operation of
the whole winter is presented then. The system operated only on weekdays from around
7:00 am to 17:00pm, 10 hours a day.

In which Q is the obtained heat or released heat rate, E is the electrical rate; and Q is calculated from Eq.(2)Q c U G (Ti ,out  Ti ,in )(2)

Where i represents 1 or 2 in the paper, which means primary or secondary side of the heat pump unit. c isthe specific heat of the water, U is the density of water and G is the flow rate of water.

Figure 5 Inlet and outlet water temperature of GSHP 1# in 2015.1.27

Figure 4. Outside air temperature variation in winter season
Figure 6 COP of GSHP1# in 2015.1.27

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GSHP Unit2
GSHP 2# provides heating for radiation system of the second and third floor. Figure 7
presents inlet and outlet water temperature variation of the primary (T1in, T1out) andsecondary side (T2in, T2out) of GSHP 2#. It is known from Figure 7 that HP 2# works fromaround 7:00 am to 14:00 pm in this day. Since outside temperature decreases quickly, T2inand T2out increase from 29Υ to 35Υ and 35Υ to 43Υ respectively about 5Υ temperature
difference, and T1in and T1out is about 13 and 7Υ, respectively. Totally 680 kWh heat is
supplied to the building. The average hourly coefficient of performance (COP) in this day is
about 4.6 as shown in Figure 8.

Figure 9 Room temperature and outside air temperature variation in January 27th (GSHP2#)
5.1.2 System Operation in Winter Season

Figure 7 Inlet and outlet water temperature of GSHP 2# in 2015.1.27

Figure 10 Water temperature variation of primary and secondary side of GSHP2# during winter season

The winter operation started from 15th November to end of March (Figure 10). GSHP
2# provides hot water for radiation system, When T2out and T2in is about 37 and 32Υ at the
beginning. They increase to 43Υand 37Υ at mid of December, and downs to around 37 and32 Υ at the end of Dec. T1in and T1out water temperatures remains at 15 and 10 Υ
respectively at the beginning of the winter season, and decrease slightly as operation
continues, that T1in keeps around 15, and T1out downs to around 8.5Υ.
Figure8 COP of GSHP2# in 2015.1.27

Room temperature in working hours and outside air temperature variations areplotted in figure 9. The outside temperature goes down to -7.3 at around 7:00 and the room
temperature is about 19.5 at the point. During the rest of the time room temperature keeps
above 20Υ,and at around 14:00, room temperature raise to about 25Υ, even without GSHP
system operation, room temperature keeps above 20Υ all the time.

11

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original data are used to plot this relation. Since COP is influenced by several factors such as
soil temperature, room heating load, T1in, T2out, Heat pump et al, A simple relation could
not be found by either one factor. By the measurement data, a rough and simple trend isfound from the figure that COP increases with a decrease of T2out. Thus, a linear relation isshown in figure 13 and R2 is about 0.0177.

Figure 11 Water temperature variation of primary and secondary side of GSHP 1# during winter season

GSHP 1# provides hot water for fresh air system and room radiator (Figure 11), T2out
and T1in are about 45 and 40Υ respectively which are 3Υ higher than those of the radiation
system. T1in and T1out are about 15Υ and 10Υ respectively.

Figure 13 relationship between T2out and COP of GSHP1#

Figure 14 Relationship between T2out and COP (GSHP2#)

Figure 12 COP of GSHP1# and GSHP 2# in winter season

Figure 14 is the relation between COP and T2out. Data of T2out gets from heat meter,
about 3000 original data are used to plot this figure. A rough trend demonstrates that COP
increase with a decrease of T2out, Thus a linear relation is shown in the figure and R2 isabout 0.1337.

COP of GSHP 1# and 2# in the winter season are shown in figure 12. Black points
represent COP of GSHP 2#, which decreases gradually as system operation continues fromabout 5.5 to 4.8 and the average COP was about 5.0. Grey points are COP of GSHP1#,
which decreases faster than that of GSHP 2#, with an average about3.9.
5.1.3 Discussion
Since GSHP 2 serves radiation system for the radiation terminal that requires a lower
supply water temperature (T2out)to the room in the winter season, and in this building, thesupply hot water temperature is set at approximately 37Υ at the beginning, about 5 lower
than GSHP1 unit which provides hot water for Fresh Air Unit (43Υ) and room radiators(43Υ) at the beginning of the winter season (this temperature will increase with outside airtemperature decrease). It is known that a relative low supply hot water temperature is betterfor heat pump performance, as the two GSHP units have almost the same primary side inlet
and outlet water temperatures, COP of GSHP2# is much higher than that of GSHP 1# unit.
Figure 13 is the relationship between COP and secondary side outlet (supply to room,
secondary T2out) water temperature. Data of T2out is get from heat Meter. About 3000

13

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System operation on July 15th is analyzed, in which GSHP 1# works half day (absorption
chiller works the half day), and system operation in whole summer seasonal is analyzed later.

Figure 17 Primary and secondary side water temperature variation of GSHP 2# on July 15th
Fig 15 Outside and indoor air temperature variation in winter season

Outside and indoor air temperature variations in winter season are shown in Fig.15.
The air temperature is above 20Υ during these periods no matter how low the outside airtemperature is. In January, indoor air temperature raises gradually and is above 23Υ for themost of the time. Therefore, GSHP system operation, especially daily interval operation,
could keep air temperature above the limitation.
5.2
Summer Season Operation
5.2.1 System Operation in Typical Day

Figure 17 presents operation of GSHP2# on July 15th when outside air temperature
is about 31Υ, T1in and T1out are around 28Υand 23Υ respectively, with 5Υ temperature
difference and about 1Υtemperature increase after the one day operation. Moreover, after
one day operation, T2out decreases from about 15Υ to about 10Υ, about 5Υ decreases,
and T2in varies in a similar pattern.
COP of GSHP 2# varies between 4 and 6 and about 4.8 as an average as shown in
Figure 15. COP of GSHP 2# is marked as 4.6 at under the standard condition, which isinferred that operation of the system in the day is better than the standard condition.

Figure 18 COP of GSHP 2#

Figure 16 Outside air temperature variation in summer season

Outside daily air temperature in the summer season of 2015 is plotted in figure 16.
The highest air temperature is around 40Υ and the lowest is around 22Υ.
Solar thermal and absorption chiller is priority-of-use, and GSHP 1# serves as a
backup. Since solar radiation is relatively sufficient in this summer, GSHP1# works only
when absorption chiller rests. Additionally, GSHP2# works the same as its operation in winter.
Under this operation principle,

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Figure 19 Primary and secondary side water temperature variation of GSHP 1# in July 15

Research PaperthFigure 19 presents operation of GSHP 1# in the same day. Since absorption chiller
operated in priority before 13:00, T1in and T1out of GSHP1# are around 28Υand 23Υ
respectively, with 5Υ temperature difference. Inlet and outlet water temperatures increase1Υ in the one day operation. T2in and T2out are around 12Υ and 15Υ. COP of GSHP 1# isaround 3.0 as shown in Figure 20.

Figure 20 COP of GSHP 1# in July 15

From China

Figure 21 Operation of GSHP 2# in summer season

COP of the GSHP 2# in this summer is plotted in Figure 22, It is around 6.5 at the
beginning, and decrease slightly into 5.0, with an average of about 5.4 in the whole season.
GSHP 1# works for a few days, while seasonal operation of GSHP 1# are not introduced
here.

th

5.2.2 System Operation in Summer Season
Summer operation starts from June 1st to end of August. Figure 21 records watertemperature variations of the primary and secondary side of GSHP 2# in this period, except
data record missing from July 23rd to August 5th. GSHP2# provides chilled water forradiation system, with supply and return water temperatures of about 10 and 15 Υ
respectively, which is much higher than normal chiller equipment. While chilled water fromthe Heat Pump (HP) unit to the ground is about 27Υ, after heat exchange, water enters into
HP unit is at about 22Υ.

Figure 22 COP of GSHP 2# in summer season

Figure 23 Relationship between water temperature and COP

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Figure 23 shows the relationship between COP and T2out.The Y axis is T2out and
the X axis is COP. About 3 months of data are arranged and about 1500 points are used toanalyze this relation. A rough linear relation is found between the two parameters, that COP
increased gradually with the increase of the secondary side outlet water temperature T2out.

From China

Table 3 Standard uncertainties of the direct measured quantities in the projectmeasured quantities

symbols of
uncertainties

units

distribution

types-B Standard
uncertainties

value

1

T1in/T1out/T2in/T2out/Tsoil

U(T)

ć

Uniform±0.1/ɰ3

0.058

2

Gf

U(Gf)

m3/h

Uniform±0.01/ɰ3

0.006

3

E

U(E)

kW

Uniform±0.5/ɰ3

0.289

4

Q

U(Q)

kW

5

COP

U(COP)



number

combine uncertaintiesvalue

ɰU2(T)+U2(Gf)0.058

ɰU2(T)+U2(Gf)+U2(E)

0.294

6.

Soil Temperature Variation
Ground is the heat source and sink of the energy system. The heat is extracted orreleased to the ground through the borehole tube. There are 70 boreholes with a total lengthof 5000m distributed in the open space around the building. Double and single boreholetubes are arranged for experiments. Water temperature variation at the inlet and outlet side
is analyzed previously. The soil temperature variation around the tube is monitored as well tocheck the impact of system operation to the ground.

Fig 24 outside and indoor air temperature variation in summer season

Indoor air temperature in summer period is plotted in Fig 24. The temperature varies
from 24Υ to 27Υ for most of the time. Since GSHP units stops working after 17:00 on
weekdays, indoor room temperature shows a little fluctuation, but varies within 3 degrees.
Therefore, good building envelops greatly benefit the maintaining of indoor temperature, andoperation of GSHP unit also contributes to it.
5.3

Error Analysis of the Measurement Data
The uncertainties of the direct measured quantities can be obtained by the generalprinciples for the determination of Type A and Type B uncertainties[21]. Since all the data
used in this paper were measured only once, Type B uncertainty is utilized to analysis thedata error. Table 2 and 3 gives the stated accuracies of the direct measured quantities in the
project and the standard uncertainties of the direct measured quantities, respectively.
Table 2 Accuracy levels of the measuring instruments
Direct Measured Quantities

Measuring Instruments or Sensors

Measuring Range

Accuracy

inlet water temperature

PT10000.0-99.9±0.1

outlet water temperature

PT10000.0-99.9±0.1

water flow rate

magnetic flow meter

0-9999.99m3±0.01

electricity consumption

three-phase electric energy meter Acrel
DTSD1352
PT10000.0-99.9

soil temperature\

VG±0.1

The Combined uncertainty of heat transfer rate and COP is calculated by method RSS[21]19.Figure 25 Soil temperature variation in double U-tube side

Soil temperature at -10, -20, -40, -80 and -100m in double U-tube side are monitored
and plotted in Fig 25. During almost 2 years of the energy system operation, soil temperatureappears a fluctuation variation with season switch. Soil temperature increases in the summer
season, but remains constant in the following months and decreases in the winter season.
During the first year from 2014/7/3 to 2015/7/3, soil temperature in depth of -10, -20, 40,-85 and -100m increases about 0.8,1,0.8,0.3 and 0.2Υ, respectively, and decreases to its
original or even lower level after the winter season operation. Compared with the second
summer period, soil temperature at the some depths has an even higher increase than in thefirst summer period. For instance, as depths of -10m, the soil temperature increases about
0.8 and 1.3Υ in the summer of 2014 and 2015 respectively, but the soil temperature at depthof -40m and -85m in 2015 changed almost to the same extent as it in 2014, which verified
that soil temperature at lower depth is more sensitive to the solar radiation. It is also found20

Research Paper

From China

from the figure that at depth of -40m soil temperature are more easily increase to the peak insummer and downs to the valley in winter than the temperature variation at other depth
which inferred that heat change happens mainly in the middle part of the U-tube.
Due to a good soil temperature variation, we could conclude that the released andextracted heat amount kept in a good balance which promise a good environment of good
GSHP operation condition, it also infers that the operation of the system is relatively good sofar.

Figure 26 Soil temperature variation in southern side

Two observation wells are placed in single U-tube field, marked as North A and B in
figure 2. Since single U-tube is 60m deep, soil temperature of well A at depth of -10m, -20m,-30m, -40m and -70m are measured, and their variation with seasons are shown in figure. 27.
The soil temperature shows a higher fluctuation along with seasons in different depth. For
instance, at depth of -10m, it increases about 2.2 and 2.8Υ respectively in two summer
seasons compared to original temperature; and in the depth of -20m, it varies about 1.6Υand 1.7Υ, respectively. While, it varies about 1.0Υ and 0.8Υrespectively at depth of -30m,
and it varies 0.6Υ at depth of -40m at and 0.2Υrespectively compare to its original soil
temperature in two summer seasons. Nevertheless, they could return to their original levels
after the winter season operation.
7.

Contribution of the GSHP to the Nearly Zero Energy Building
About 30000 kWh heat is provided to the building by heat pump2 in the winter season.
The floor area of 2nd and 3rd is roughly 2000m2, daily operation hour is roughly 10 hours,
system operation about 100 days in this winter, so the heat load of the heat pump 2 is about
14.6W/m2.
There are solar thermal, WLHP, WS-VRV and GSHP system worked together toprovide heating and cooling of the building, and it is calculated that there are about
64400kWh heat is supplied totally in winter season from Nov. 2014 to Mar. 2015, and
48500kWh heat is directly supported by GSHP system, if contribution ratio is calculated byration of suppled heat and required heat, then contribution ratio of GSHP is about 75.3. Whilein summer season, there are totally 3000kWh cold is provided by GSHP units, and
51000kWh cold is provided by the energy system, so the contribution ratio is about 57.8%.

21

Research Paper

From China

GSHP worked as main energy system of the building, and it performed very well during theoperation.
8.

Conclusion
The paper mainly introduces a GSHP system operation and its performance in anearly zero energy building. The system operation during Nov. 1st 2014 to Sep. 30th 2015 isanalyzed based on measurement data.
GSHP system works splendidly in this building, that average COP in the winterseason is about5.0 and 3.9, and is about 5.4 in the summer season. GSHP units works fortwo different terminal systems, which is found from monitoring data that GSHP unit forradiation system has a better performance than that works for fan coil unit and radiator in thewinter season, since radiation system needs a lower supply of water temperature in winterand higher supply of water temperature in the summer which is just good for heat pump
performance in both winter and summer.
The room temperature maintains above 20Υ,and variates between 20 and 23Υ inthe whole winter season, and it fluctuates from 25 to 27Υ during summer season㸦including
non-working hour㸧by the operation of the energy system. The steady room temperature
variation and good indoor environment. infer a relatively good operation of the energy system.
The soil temperature in different depths are monitored and they goes to the peak inthe summer, and could recover prominently in the winter season. After two years’ operation,
the soil temperature in different depths recover to their original level, which provide a good
operation environment for GSHP system operation.
The application of GSHP system in nearly zero energy building is a promising
roadmap. Good envelop and airtightness provide a relatively low indoor heating and coolingload, which provides advantages for combination of GSHP and radiation system. The
performance of the GSHP is relatively good, that even 10 hours’ operation during weekday
and non-operation at weekends could satisfy the requirement of the room environment.
ACKNOWLEDGEMENT
This research is supported by financial support from the National Key Technology R&D
program in the 12th Five Year Plan of China Key Renewable energy utilization to achieve
higher energy efficiency target(No. 2014BAJ01B03)
Reference[1] Zhihua Zhou, LeiFeng, Shuzhen et al, The operational performance of “net zero energy
building”: A study in China, Applied Energy 177(2016) 716-728[2]Muhammad Waseem Ahmad, et al, Building energy metering and environmental
monitoring –A state –of –the art review and directions for future research, Energy and
Buildings 120 (2016) 85-102[3] Limei Shen, Xiwang Pu, Yongjun Sun et al, A study on thermoelectric technology
application in net zero energy buildings, Energy, 113(2016) 9-24
[4] Sheng Zhang, Pei Huang, Yongjun Sun, A multi-criterion renewable energy systemdesign optimization for net zero energy buildings under uncertainties, Energy, January 2016,
pages 654-665[5] Shicong Zhang, et al, Operation performance in cooling mode of a ground source heatpump of a nearly –zero energy building in the cold region of China, Renewable Energy
87(2016) 1045-1052[6] Huai Li, Katsunori Nagano, Yuanxiang Lai, Kazuo Shibata, Hikari Fujiimoto. Evaluating
the performance of a large borehole ground source heat pump for greenhouses in northern
Japan, Energy 2013. Volume 63, pages 387-399.
[7] Weijuan Sun, Pingfang Hu, Fei Lei, Na Zhu, Zhangning Jiang, Case study of performance
evaluation of ground source heat pump system based on ANN and ANFIS models, Applied
Thermal Engineering, Volume 87,5 August 2015,Pages 586-594

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Research Paper

From China[8] Neng Zhu, Jingmei Wang 㸪 Performance evaluation before and after solar seasonal
storage coupled with ground source heat pump㸪Energy Conversion and Management㸪
Volume 103, October 2015, Pages 924–933[9] Yujin Nam, Ho-Byung Chae, Numerical simulation for the optimum design of groundsource heat pump system using building foundation as horizontal heat exchanger, Energy 73(2014)933-942[10] Molina Giraldo N, Bayer P, Blum P. Evaluating the influence of thermal dispersion ontemperature plums from geothermal system using analytical solutions. Int J,Therm Sci
2011;50;1223-31[11] X.Q, Zhai, X.W.Cheng, R.Z.Wang, Heating and cooling performance of a minitype
ground source heat pump system. Applied Thermal Engineering, xxx (2016) xxx-xxx, article
in press[12] B.Hu,Y.Li et.al Extremum seeking control for efficient operation of hybrid ground souceheat pump system, Renewable Energy 86 (2016) 332-334[13] N.Zhu,J,Wang, Li,liu, Performance evaluation before and after solar seasonal storage
coupled with ground source heat pump, energy Convers.Manage.103(2015) 924-933[14] P.Shen,J.R.Lukes, Impact of global warming on performance of ground source heatpumps in US climate zones, Energy Convers. Manage. 101(2015) 632-643.
[15] Huai Li , Katsunori Nagano, Yuanxinag Lai, A new model and solutions for a spiral heatexchanger and its experimental validation. International Journal of Heat and Mass transfer,
Volume 55 Issues 15-16,July 2012, Pages 4404-4414[16] Giuseppe Emmi, Angelo Zarrella, Michele De Carli, Antonio Galagaro, An analysis ofsolar assisted ground source heat pump in cold climates, Energy Conversion andManagement, Volume 106, December 2015, Pages 660-675[17] Shicong Zhang, YiQiang Jiang, et.al. Operation performance in cooling mode of aground source heat pump of a nearly-zero energy building in the cold region of China,
Renewable Energy 87(2016) 1045-1052[18] Rui Fan,Yiqiang Jiang, Yang Yao et.al. A study on the performance of a geothermal heatexchanger under coupled heat conduction and groundwater advection, Energy 2008. Volume32, Pages 2199-2209.
[19]Aymeric Girard, Eulalia Jadraque Gago, Tariq Muneer, Gustavo Caceres, Higher groundsource heat pump COP in a residential building through the use of solar thermal collectors,
Renewable Energy, Volume 80, August 2015, Pages 26-39[20] Mohamad Kharseh, Mohammed Al-Khawaja et al, Potential of ground source heat pumpsystems in cooling-dominated environments: Residential buildings, Geothermics, Volume 57,
September 2015, Pages 104–110[21] Measurement Uncertainty Analysis Principles and Method, NASA Measurement Quality
Assurance
Handbook-ANNEX3.
2010-07-13

Research Paper

From Thailand

Load Variations with Seasonal Conditions Affected to Coefficient of Performance ofAir to Water Heat Pump
Amornrat Kaewpradap, Piyatida Trinuruk and Surachai Sanitjai
Department of Mechanical Engineering, Faculty of Engineering, King Mongkut’s University ofTechnology Thonburi, Thailand
Introduction
Air to water heat pump is a device that transfers heat energy from air source to water sink.
Heat pump consists of four main components such as compressor, evaporator, condenser
and expansion devices. Moreover, air to water heat pump is denoted as technology for
producing hot water with higher energy efficiency. Nowadays, heat pumps are supported by
Ministry of Energy in Thailand to apply widely because of high efficiency, decrease ofemission and energy conservation. Regarding heat pump efficiency, the ratio between
thermal energy and electrical energy as coefficient of performance (COP) was defined byheating process. Following European standard EN255-3 [2] which consists of heating-up
period, hot water tapping period, determination of reference hot water temperature, standby
and determination of the maximum quantity of usable hot water in single tapping. During hot
water tapping period, there is tapped equivalent to 15.0 L/min of outlet water flow rate.
Coefficient of performance for tapping process (COPt) was defined the performance of heatpump [3]. Study of the seasonal performance rating of heat pump water heater was
discovered that the range of ambient air temperature hot water temperature and humidity
affected to COP [4]-[6]. However, COP obtained from previous study was analyzed byheating process which was not reflected to actual application. To investigate the performanceof heat pump with actual utilization load, COPt based on EN255-3 standard is analyzed forthis study. As the variation of temperature among different seasons were effected to COP, it
is necessary to investigate load variations such an outlet hot water temperature with ambient
temperature and air humidity and from air to water heat pump.
Methodology
The experiment was operated based on EN255-3 standard which the load variations as
outlet hot water temperature and the variation of temperature among different seasons asambient temperature and air humidity from air to water heat pump were studied. The
experimental conditions are adjusted at the range of ambient temperature between 18-34oC
and %RH=50-80.

Fig.1 Operating cycle of heat pump based on European standard (EN255-3).

23

24

Research Paper

From Thailand

The heat pump is set as inlet water temperature at 25oC and outlet water temperatureinterval between 40-55oC. The operating cycle of heat pump based on European standard
EN255-3 is shown in
Fig. 1. The first stage is heating-up period, which is started fromturned on heat pump until turned on thermostat. The second stage is tapping process fordetermination of COPt, which volume of hot water is tapped equivalent to half of nominal
volume of hot water storage tank, reheated until the water temperature reach the setting
point. The third stage is called a determination of reference hot water temperature which
volume of hot water is tapped until the hot water temperature below 40ºC. The fourth stage isstandby period, which is a determination of standby power input. To obtain standby power
input, Outlet water temperature in storage tank is dropped to 5oC, heat pump is turned on tosetting point and it is called 1 cycle. The operating for number of cycles should not be
operated less than 24 hours and at least 3 cycles. Final stage is a determination of the
maximum quantity of usable hot water in single tapping, the volume of hot water is tapped
until the outlet water temperature below 40ºC after standby period. Corresponding toEuropean standard EN255-3 [2], the determination of COPt is calculated from measured ofoutlet water energy (Qt), electrical energy input for tapping process (Wet), standby power
input (Pes) and tapping time (tt).

Research Paper

From Thailand

Fig.2 Time series at Ta=18oC with %RH=60% based on EN255-3.

Results
Experimental results based on EN255-3 standard
The results show five stages of heat pump testing based on EN255-3 as heating-up period,
hot water tapping period, determination of reference hot water temperature, standby anddetermination of the maximum quantity of usable hot water in single tapping. Figure 2 shows
the time series of experimental results at Ta=18 oC with %RH = 60%. Following EN255-3
standard, outlet water temperature flow rate of tapping hot water and power input (P) wereanalyzed as shown in Fig.3. The results show 5 stages of operating cycle of heat pumpexperimented by EN255-3 standard. Firstly outlet water temperature was increased from
25oC -55oC which affected to higher power while almost constant water tapping flow rate
was obtained for heating-up stage. Secondary, followed by EN255-3 standard, two times ofwater tapping and less 10% difference of obtained outlet water energy were experimented.
As the results, heat pump was operated when water was tapped and outlet watertemperature decreases to 50oC (setting point temperature). Following tapping process
corresponding to the actual load, thus COPt was calculated to evaluate performance of heatpump.
Effects of ambient temperature (Ta) related with air humidity (%RH)

Fig.3 Relations between Ta and COPt for %RH=50%, 60%, 70% and 80%.

Effects of ambient temperature (Ta) related with outlet hot water temperature (Two)This result shows relations between Ta and tt for Two = 40 oC, 43 oC, 43 oC, 49 oC, 52 oC
and 55 oC. As the above results, lower tapping time was induced by higher ambient
temperature, moreover it was affected by lower outlet water temperature owing to decreaseof required outlet water energy outlet water energy. Figure 4 shows relations between Ta andWet for Two =40 oC, 43 oC, 43 oC, 49 oC, 52 oC and 55 oC. When ambient temperature
was higher with lower outlet water temperature, Electrical energy input for tapping process islower due to lower load of compressor. The overshot electrical energy input was observed at
specified ambient temperature for each outlet water temperatures and resulted to diminish
COPt significantly as illustrated in Fig.5.

As the results based on EN255-3 as shown in Fig.2, tapping time, outlet water energy,
electrical energy input for tapping process and COPt were analyzed. To study the effects ofload variations, ambient temperature were increased from 18 to 34oC and air humidity wasraised from 50% to 60%, 70% and 80%. The result shows increasing of ambient temperature
brought about lower tapping time and electrical energy input data , however outlet waterenergy were almost constant with ambient temperature variations. It was because of higher
thermal energy caused by increase of ambient temperature which was absorbed byrefrigerant in evaporator and affected to decrease of tapping time. Moreover, higher COPt
was slightly affected by higher air humidity due to the droplet deposition rate on evaporator
increased with air humidity, which released latent heat was greater than sensible heat [7]. As
the results, the increase of ambient temperature enhances COPt due to increase of heatsource induced higher COPt followed by thermodynamics laws as shown in Fig.3.

Fig.4 Relations between Ta and Wet for Two = 4025

26

ńġ- 55ńįResearch Paper

From Thailand

Research Paper

From Thailand

Asian Heat Pump Thermal Storage Technologies Network

Fig.5 Relations between Ta and COPt for Two =40, 43, 43, 49, 52 and 55

ńįConclusion
Based on EN255-3 standard, coefficient of performance for tapping process (COPt) was
defined from performance of heat pump during tapping process. As the variation oftemperature among different seasons, the load variations of ambient temperature, air
humidity and outlet hot water temperature from air to water heat pump (11kW) were studied
to obtain COPt. This study focused on the effects of load variations from air to water heatpump by variation of Ta = 18oC, 22oC, 26oC, 30oC and 34oC. Moreover, the variation ofambient temperature was experimented with increase of Two = 40oC, 43oC, 46oC, 49oC,
52oC and 55oC and %RH = 50%, 60%, 70% and 80%. The results showed increase ofambient temperature enhanced COPt because lower electrical energy input was induced byhigher ambient temperature. Moreover, higher COPt was affected by higher air humidity
owing to the droplet deposition rate on evaporator increased with air humidity, which
released latent heat was greater than sensible heat [6]. The results were shown that
decrease of outlet water temperature affected to higher electrical energy input and enhanced
higher COPt. This study could be concluded that higher ambient temperature, air humidity
and lower outlet water temperature enhanced to higher COPt. Especially, two significant
parameters such as ambient temperature with specified outlet water temperature, theboundary of maximum COPt = 3.99, 4.10, 4.20, 4.24 and 4.52 for Ta = 18 oC, 22 oC, 26 oC,
30 oC and 34 oC for air to water heat pump was obtained.
References[1] Heap, R.D., 1983, Hear pump, 2nd ed., E. & F.N. Spon. London, p.3.
[2] BS EN255-3, 1997. Air conditioners, liquid chilling packages and heat pumps withelectrically driven compressors – Heating mode, Part 3: Testing and requirements formarking for sanitary hot water units.
[3] Amornrat Kaewpradap, Piyatida Trinuruk and Surachai Sanitjai, 2015, Study of Energy
Performance of Heat Pump used in Thailand, Proceedings of The 6th TSME International
Conference on Mechanical Engineering, Regent Beach Cha-am Hotel, Petchburi, Thailand,
pp.92.
[4] G.L. Morrison, et al., Seasonal performance rating of heat pump water heaters, Universityof New South Wales, Solar Energy. Vol.76, 2004, pp.147-152.
[5] J.J. Guo, et al., Experimental research and operation optimization of air-source heatpump water heater, Shanghai Jiao Tong University, Applied Energy. Vol. 88, 2011, pp.41284138.
[6] Hae Won Jung, et al., Performance comparison between a single-stage and a cascade
multi-functional heat pump for both air heating and hot water supply, Korea University,
International Journal of Refrigeration. Vol. 36, 2013, pp.1431-1441.
[7] Bu Xu, et al., Experimental investigation of the performance of micro channel heatexchangers with a new type of fin under wet and frosting conditions, Shanghai Jiao Tong
University, Applied Thermal Engineering. Vol. 89, 2015, pp.444-458.

27

To promote energy savings and combat global warming, there is an urgent need to spread efficientheat pump and thermal storage technologies on the demand side. Countries in Asia, which areenjoying rapid economic growth, should coordinate with one another to spread this technology.
Five to ten years from now, Asia will become a global economic powerhouse and heat pumptechnologies will play a considerable role in all sectors. Asian countries will therefore need toaddress common issues and problems that have already been faced in Europe and North America.
Concerning the building of connections and networks among countries, it is essential to share
information on diffusion policies, technology trends, applications, etc., and then to make incremental
improvements. Further, situations which can or should be handled through collaboration should be
handled flexibly, on a case-by-case basis, with the collaboration of all countries.
In order to encourage the use and development of heat pump and thermal storage technologies in
Asian countries we have established AHPNW in 2011.

Participating Countries and Entities
CHINA: China Academy of Building Research (CABR)INDIA: The Energy and Resources Institute (TERI)JAPAN: Heat Pump and Thermal Storage Technology Center of Japan (HPTCJ)KOREA: Korea Testing Laboratory (KTL)VIETAM: Hanoi University of Science and Technology (HUST)THAILAND: King Mongkut’s University of Technology Thonburi (KMUTT)INDONESIA: Heating, Cooling & Thermo Fluids Technology Indonesia (HCTFTI)

Please visit our website for more information.
эhttp://www.hptcj.or.jp/e/ahpnw/tabid/571/language/en-US/Default.aspx

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