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NBSIR 81-2434

Method of Testing, Rating and

Estimating the Seasonal Performance of

Ground-Water-Source Heat Pumps

U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Laboratory

Center for Building Technology

Washington, DC 20234

August 1982

Issued November 1982

Sponsored by:

. Department of Energy

ashington, DC 20585

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NBSIR 81-2434

METHOD OF TESTING, RATING AND

ESTIMATING THE SEASONAL PERFORMANCE OF

GROUND-WATER-SOURCE HEAT PUMPS

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William J. Mulroy

U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Laboratory

Center for Building Technology

Washington, DC 20234

August 1 982

Issued November 1982

Sponsored by:

U.S. Department of Energy

Washington, DC 20585

U.S. DEPARTMENT OF COMMERCE, Malcolm Baldrige, Secretary

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director
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ABSTRACT

The National Bureau of Standards has made a study of the part-load and seasonal

performance of residential water source heat pumps operating in both heating

and cooling modes. This document outlines methods for testing and rating these

units which account for the variation in performance due to part-load operation

and change in source water temperature. A calculation procedure is presented

which can be used to estimate the seasonal performance and seasonal cost of

operation of residential water source heat pimips.

Key Words: Central air conditioners; central heating equipment; heat pumps;

heating seasonal performance; rating procedure; residential

heating; seasonal cost of operation; seasonal performance; test

method

ill
TABLE OF CONTENTS

Page

ABSTRACT

LIST OF TABLES; LIST OF FIGURES vi

NOMENCLATURE

SI CONVERSION FACTORS x

1. INTRODUCTION 1

1.1 SCOPE AND PURPOSE 1

2. RECOMMENDED TESTING AND RATING REQUIREMENTS 2

2.1 INTRODUCTION 2

2.2 TEST REQUIREMENTS 3

2.2.1 General Test Condition Requirements for all Tests ^ 2.2.2 Steady-State Test Conditions 4

2. 2. 2.1 Test E, High Temperature Cooling Test

Conditions 4

1 . 1 . 1.1 Test F, Low Temperature Cooling Test

Conditions 4

2. 2. 2.

Test G, High Temperature Heating Test

Conditions 5

2. 2. 2.

Test H, Low Temperature Heating Test

Conditions 5

2.2.3 Test Conditions for Optional Dry Coll Steady-State

and Cyclic Cooling Tests ^ 2.2. 3.1 Optional Test I, High Temperature Dry Coll

Cooling Test Conditions 5

2. 2. 3.

Optional Test J, Low Temperature Dry Coll

Cooling Test Conditions 3

2. 2. 3.

Optional Test K, High Temperature

Cyclic Cooling Test Conditions. c 6

2. 2. 3.

Optional Test L, Low Temperature

Cyclic Cooling Test Conditions 6

2.2.4 Optional Cyclic Heating Tests 6

2. 2. 4.1 Optional Test M, High Temperature Cyclic

Heating Test Conditions 6

2. 2. 4.

Optional Test N, Low Temperature Cyclic

Heating Test Conditions 7

3. HEAT PUMP PERFORMANCE TEST PROCEDURES 8

3.1 INTRODUCTION 8

3.2 STEADY-STATE TEST PROCEDURES 8

3.2.1 Available Test Methods 8

3.2.2 Air Flow Rate, Instrumentation and Data to be

Recorded 9

3.2.3 Test Preparation and Performance 11

3.2.4 Test Tolerances 11

3.2.5 Data Analysis and Results 11

iv
TABLE OF CONTENTS (cont.)

Page

3.3 CYCLIC TEST PROCEDURES 12

3.3.1 Available Test Methods 12

3.3.2 Air Flow Rate, Instrumentation and Data to be

Recorded 13

3.3.3 Test Preparation and Performance 13

3.3.4 Test Tolerances 14

3.3.5 Data Analysis and Results 14

4. CALCULATION OF THE COOLING SEASONAL PERFORMANCE FACTOR (CSPF),

HEATING SEASONAL PERFORMANCE FACTOR (HSPF) AND SEASONAL COST OF

OPERATION 16

4.1 DISCUSSION OF THE CALCULATION PROCEDURE FOR SHALLOW GROUND

WATER SOURCE APPLICATIONS 16

4.2 CALCULATING CSPF, HSPF AND SEASONAL OPERATING COST FOR GROUND

WATER SOURCE HEAT PUMP APPLICATIONS 16

REFERENCES 22

APPENDIX A: SAMPLE CALCULATIONS FOR GROUNDWATER SOURCE APPLICATIONS ... A-1

V
LIST OF TABLES

Page

Table 1 Summary of Test Conditions 23

Table 2 Cyclic Test Options 24

Table 3 Steady-State Test Tolerances 25

Table 4 Tolerances for the On-Period Portions of Cyclic Performance

Tests K,. L, M, and N 26

Table 5 Design Conditions for Six Standardized Climatic Regions 27

Table 6 Fractional Temperature Bin Hours for Cooling Season

Calculations 28

Table 7 Fractional Temperature Bin Hours for Heating Season

Calculations 29

Table 8 Standardized Design Heating and Cooling Requirement Values

(kBtu/h) 30

Table 9 Example of Information which would Assist a Consumer in

Purchasing a Heat Pump 31

LIST OF FIGURES

Figure 1. Actual heating load hours (HLH^) and regional heating

load hours (HLH„) for the United States 32

K

Figure 2. Distribution of cooling load hours throughout the

continental United States to be used in estimating the

seasonal operating cost of central air conditioners and

heat pumps operating in the cooling mode 33

Figure 3. Average temperature of shallow ground water in degrees

Fahrenheit 34

vi
NOMENCLATURE

BL(Tj) Building load at an outdoor dry-bulb temperature Tj, kBtu/h (kW)

Degradation factor for cyclic operation, defined by equation 3.3

CLF Cooling load factor, defined as the ratio of the total cyclic

cooling done in a complete cycle or specified period consisting

of an "on"-time and an "off*—time to the steady-state cooling done

over the same time period at constant ambient conditions. See

equation 3.4.

CLH Cooling load hours, defined as the number of hours in a cooling

season that a building requires cooling. See table 5.

COP Coefficient of performance, defined as the net heating done over a specified period of time divided by the total electrical energy input over the same time interval.

^pa Specific heat at constant pressure of air-water mixture per pound

of dry air, Cp^ = 0.24 + 0.444 W^, Btu/lb®F, (1.01 + 1.86 Wj^,

kJ/kg*°C).

CSPF Cooling seasonal performance factor; defined as the ratio of the

total cooling done to the total energy usage over a cooling season.

E Total seasonal electrical energy usage, kW.

Ess(T) Steady-state total power input at a water temperature T, kW.

HLF Heating load factor, defined as the ratio of the total cyclic

heating done in a complete cycle of specified period consisting

of an "on"-time and "off'-time to the steady-state cooling done over

the same time period at constant ambient conditions. See

equation 3.4.

HLH Heating load hours, defined by table 5.

HS?F Heating seasonal performance factor; defined as the ratio of the

total heating done to the total energy usage over a heating season.

j Outdoor dry-bulb temperature bin number, see tables 6 and 7.

LF Load Factor, defined as the ratio of the total cyclic cooling or heating done in a complete cycle of specified period consisting

of an "on”-time and "off'-time to the steady-state cooling or heating done over the same time period at constant ambient

conditions. See equation 1.2.

N Total number of temperature bin hours.

N

Fractional number of temperature bin hours, see tables 6 and 7.

vil
PLF Part-load factor, defined as the ratio of the cyclic COP to the

steady-state COP, see equation 4.30.

Q Total seasonal cooling or heating done, kBtu (kJ).

Qcyc Total cooling or heating done over a cycle consisting of one compressor "off" period and one compressor "on" period, kBtu (kJ).

•Qgg(T) Total steady-state cooling or heating capacity at a water temperature

T, kBtu/h (kW).

Qcyc Cyclic total capacity defined as the ratio of the total cooling done

over a given time period to the duration of time the compressor is on

in that period, kBtu/h (kW).

Qgg Steady-state capacity, kBtu/h (kW)

RH(T.) Resistance heat energy usage in temperature bin; kW - h, see equation

4.31.

SPF Seasonal performance factor; defined as the ratio of the total cooling

or heating done to the total energy usage over a cooling or heating

season.

Tj Representative outdoor dry-bulb temperature for temperature bin j, *F

(®C). See tables 6, 7.

Tai(t) Dry-bulb temperature of air entering the Indoor coil, ®F (*C).

Ta2(^) Dry-bulb temperature of air leaving the indoor coil, *F (“C).

t Time, hours

ton Duration of time the compressor is on in one cycle consisting of a compressor on-time and a compressor off-time, hours

V Indoor air flow rate, cfm (m^/s), at the dry-bulb temperature, humidity

ratio, and pressure existing in the region of measurement.

v^ Specific volume of air-water mixture, at the same dry-bulb temperature,

humidity ratio, and pressure used in the determination of the indoor air

flowrate, ft^/lb (m^/kg).

Wjj Humidity ratio, Ib/lb (kg/kg).

X(T 4 ) Load factor at an outdoor dry-bulb temperature T^, defined by equation

^ 4.29.

viii
j - Temperature bin number, see Table 3

c - cooling

H - heating

X - Same as X(Tj)

T - Time period consisting of a compressor on-time and compressor

off-time [h]

r - Defined by equation 3.2, ®F.

SUBSCRIPTS AND SUPERSCRIPTS

ss - steady-state

eye - cyclic

dry - dry-coil

ix
SI CONVERSION FACTORS

Multiply ®y To Obtain

Btu, IT 1.055 kJ

Btu/h, Btuh 0.293 W

Btu/lb“F, c, specific heat 4.19 kJ/kg*(

“F *C - (*F-32)/1.8

ft 0.3048 m

ft/min, fpm 0.00508 m/s

ft^/lb 0.0623 m^/kg

ft^/min, cfm 0.472 —

gpm (US) 0.0631 —

inch 25.4 Him

inch of water 3.38 kPa

kBtu/h 1055 kJ

Ib/h 0.126 g/s

X
1. INTRODUCTION

1.1 SCOPE AND PURPOSE

The recommended test and rating procedures proposed herein are intended to be

applied to packaged, unitary, ground'-water-to-air heat pumps, driven by single

phase electric power which are intended for residential applications. They do

not apply to water source heat pumps used for infrastructure heat transfer, air

source heat pumps, hybrid systems which supplement the heat pump output by

burning fossil fuel, to two speed compressor units, or to units with two

compressors

The steady—state rating points proposed herein were chosen to be in conformance

with ARI (Air Conditioning and Refrigeration Institute) Standard 325-82, "Ground

Water Source Heat Pumps" 11] . This rating procedure differs from that of ARI

325-82 in that it includes procedures for calculating seasonal efficiency and

cost of operation and does not include quality, reliability or safety criteria.

Also the procedure herein includes test series (Tests I, J, K, L, M, N) which

may be employed if one wants to predict either the potential degradation

because of cycling phenomena in situ or the merits of a particular off-cycle

innovation (e.g., auto-switch for crankcase heater). Typically, these cycling

effects could cause a difference between seasonal and steady-state of the order

of 10%. The steady-state tests (E, F, G, H) would be expected to yield the same

ratings as the ARI procedure.

The recommended testing and calculation procedures are intended to provide

ratings comparable to those resulting from the current air source heat pump

test procedures [3, 4],

Rating points and calculation procedures for solar-water-source heat pumps are

not covered because of the lack of standardization in system design for this

application. It is believed, however, that the data resulting from tests

according to this Test Procedure would allow calculation of the seasonal efficiency and energy cost for many solar systems once their design has been estabblished. Water-source heat pumps for heat transfer within structures are not

covered because of the predominantly commercial nature of their application.

The purpose of these recommended test and rating requirements is, generally, to

provide performance information from which a heat pump unit may be properly

sized to a heating or cooling load, to provide information from which a consumer may estimate heating and cooling costs, and to provide information from

which seasonal energy efficiency and operating cost comparisons can be made

between heat pump models and between different types of heating systems.
2. RECOMMENDED TESTING AND RATING REQUIREMENTS

2 . 1 INTRODUCTION

The heat pump test operating conditions described in section 2.2.1 through

2.2.4 were selected to reflect the various modes of operation a heat pump may

commonly encounter. These operating points were also chosen so as to be able

to estimate the seasonal performance with a minimum amount of testing.

A steady-state cooling test at a 70°F (21.1**C) entering water temperature is

required (test E). In addition a low temperature steady-state cooling test

(test F) is required at a SO^F (10*C) entering water temperature. The addition

of the second test makes possible interpolation (or extrapolation) of the test

data to conditions other than those used for the tests.

Similarly two steady-state heating tests are required so that data interpolation

or extrapolation is possible for heating applications. An entering water

temperature of 70‘*F (21.1'*C) is specified for the steady-state high temperature

heating test (test G) and an entering water temperature of 50 °F (10°C) is

specified for the steady-state low temperature heating test (test H).

These required steady-state test conditions are the same as those required by

ARI (Air Conditioning and Refrigeration Institute) Standard 325-82.

Since properly sized heat pumps will cycle on and off to meet small heating and

cooling loads, cycling tests are included to determine the part load performance

degradation at each steady-state rating point. The percent on-time for these

tests was chosen to be 20 percent. In order to limit temperature swings inside

the house, it is common practice to design thermostats so that they cause the

unit to cycle at approximately 3 cph at a 50 percent on-time. This, assuming

the control thermostat produces a parbolic relationship between cph and ontime, results in cycling rate of approximately 2 cph at a percent on-time of 20

percent, which corresponds to a cycling period of 30 minutes. The on and offtime for the cycling tests were therefore chosen to be 6 minutes and 24 minutes,

respectively.

The cyclic cooling tests are to be performed with the same entering air

dry-bulb temperature and entering water temperatures as the steady-state

cooling rating point tests, but, because of inaccuracies in available methods

of cyclic latent cooling capacity measurement, with the entering air wet-bulb

temperature reduced sufficiently to insure a dry coll (no condensate collection). For comparison, two additional steady-state cooling tests are required

that are identical to the other steady-state rating point tests but with the

entering air wet-bulb temperature reduced sufficiently to insure a dry coil

condition.

The cyclic heating tests are to be performed at the same entering air and

water conditions as the steady-state heating tests.

The ratio of the coefficients of performance measured during comparable cyclic

and steady-state tests is used with the load factor, LF, to calculate the degradation coefficient, Cjj, of the heat pump using the following formulas:

2
CD = ( 1 . 1 )

COP

^ ~ gOP

1 - LF

eye

LF ^ %RT X Qeye

100 X (^33

( 1 . 2 )

• * ,where COP^yc, COPgg, Qcyc> Qss repectively the unit’s eoeffieient of

p^erformance , and capaeity, measured at eomparable eyelle and steady-state eonditions, and pereent RT is the pereent run time of the unit during cyelic

operation. The degradation coefficient is used in the seasonal performance

calculations described in section 4. Laboratory tests have shown that the

degradation factor varies with water temperature. In order to reduce the test

burden this variation is assumed to be linear in this test method.

It is recommended that when Cd has been determined at both high and low

temperature test points in an operational mode (heating or cooling)

values of Cq for operation in the same mode at other water temperatures be

obtained by linear interpolation or extrapolation from the two measured values.

There are a total of six tests to determine the cyclic performance of the

water-source heat pump unit (four cyclic and two steady-state dry coil tests).

Manufacturers may perform all six tests or may select one of three options (see

section 2.2) which reduce or eliminate cyclic testing, but require simplifying assumptions to be made about the degradation coefficient of the unit.

It is felt that these options were necessary in order to accommodate the small

manufacturer who might not have test facilities capable of performing the

cycling tests within the tolerances required for accuracy, or for vinits produced

in production runs too small to justify this additional testing burden.

2.2 TEST REQUIREMENTS

Heat pumps shall be subjected to the following tests described in sections

2.2.1 through 2.2.4 (test identification letters have been selected starting

with E to avoid confusion with air-source unit tests A through D of the DOE

Test Procedure for Air Conditioners and Heat Pumps) . All cooling mode tests are to be omitted for heating-only units:

Test E. High Temperature Cooling Test (omit for heating only units)

Test F. Low Temperature Cooling Test (omit for heating only units)

Test G. High Temperature Heating Test

Test H. Low Temperature Heating Test

Depending on any of the four alternatives discussed below some or all of the

following optional tests may also be performed.

Test I. Test J.

Test K.

Test L.

Test M.

Test N.

High Temperature Dry Coll Cooling Test

Low Temperature Dry Coil Cooling Test

High Temperature Cyclic Cooling Test

Low Temperature Cyclic Cooling Test

High Temperature Cyclic Heating Test

Low Temperature Cyclic Heating Test

3
In lieu of performing all six of the additional tests (test I through test N)

which are required to determine the cyclic performance at each rating point the

manufacturer may choose one of the following three options:

1) Perform the high temperature cooling cyclic test (test K) and the comparable

high temperature cooling dry coil steady-state (test I) and assume that the

resulting coefficient of degradation, C]), is typical of all cooling operation.

Perform the low temperature cyclic heating test (test N) and assume that the

resulting Cp is typical of all heating operation.

2) Assume a constant cooling value of Cp =» 0.25. Perform the low temperature

cyclic heating test (test N) and assume that the resulting Cp is typical of

all heating operation.

3) Assume a constant Cj) = 0.25 for both heating and cooling.

2.2.1 General Test Condition Requirements for All Tests

All tests shall be conducted at the standard rating conditions specified in

section 5.1.4 of ARI Standard 325-82. Table 1 summarizes the test condition

requirements for the different tests.

2.2.2 Steady-State Test Conditions

2. 2. 2.1 Test E, High Temperature Cooling Test Conditions

The high temperature steady-state cooling test shall be conducted with an entering water temperature of 70“F (21.1®C). The dry-bulb air temperature

entering and surrounding the unit shall be 80 ®F (26.7*C) and the wet-bulb air

temperature entering the unit shall be 67“F (19.4*).

The test shall be conducted according to the test procedures outlined in

section 3.2 for steady-state tests. The duration of the test shall be a minimum of 1/2 hour.

2. 2. 2. 2 Test F, Low Temperature Cooling Test Conditions

The low-temperature steady-state cooling test shall be conducted with an entering water temperature of 50“F (10*C). The dry-bulb air temperature

entering and surrounding the unit shall be 80*F (26.7“C) and the wet-bulb air

temperature entering the unit shall be 67®F (19.4*C).

The test shall be conducted according to the test procedures outlined in section

3.2

for steady-state tests. The duration of the test shall be a minimum of 1/2

hour.

4
2.2.2. 3 Test G, High Temperature Heating Test Conditions

The high temperature steady-state heating test shall be conducted with an entering water temperature of 70“F (21.1°C). The dry-bulb air temperature

entering and surrounding the unit shall be 70°F (21.1®C) and the wet-bulb air

temperature entering the unit shall not exceed 60®F (15.6“C).

The test shall be conducted according to the test procedures outlined in section

3.2

for steady-state tests. The duration of the test shall be a minimum of 1/2

hour. If elected (option 1 in table 2) , the High Temperature Cyclic

Heating test (test M, section 2. 2. 4.1) shall be performed immediately following

this test.

2. 2. 2. 4 Test H, Low Temperature Heating Test Conditions

The low temperature steady-state heating test shall be conducted with an entering

water temperatures of 50“F (lO^C). The dry-bulb air temperature entering and

surrounding the unit shall be 70“F (21.1®C) and the wet-bulb air temperature

entering the unit shall not exceed 60“F (15.6“C).

The test shall be conducted according to the test procedures outlined in section

3.2

for steady-state tests. The duration of the test shall be a minimum of 1/2

hour. If elected (option 1, 2, or 3 in table 2), the High Temperature Cyclic

Heating Test (test N, section 2. 2. 4. 2) shall be performed immediately following

this test.

2.2.3 Conditions for Optional Dry Coil Steady-State and Cyclic Cooling Tests

2. 2. 3.1 Optional Test I, High Temperature Dry Coil Cooling Test Conditions

The steady-state dry coil cooling test at a 70 °F (21.1°C) entering water

temperature shall be conducted with the same water flow rate as was used for

test E, High Temperature Cooling Test. The dry-bulb air temperature entering

and surrounding the unit shall be 80“F (26.7“C) and the wet-bulb temperature

entering the unit shall at no time exceed that value which results in the

production of condensate by the cooling coll at this test condition.

The test shall be conducted according to the test procedures outlined in section

3.2 for steady-state tests. The duration of the test shall be a minimum of 1/2

hour. The High Temperature Cyclic Cooling Test (test K, section 2. 2. 3. 3) shall

be performed immediately following this test.

2. 2. 3.

Optional Test J, Low Temperature Dry Coil Cooling Test Conditions

The steady-state low temperature dry coil cooling test shall be conducted with

the same water flow rate and 50“F (10“C) entering water temperature as was used

for test F, Low Temperature Cooling Test. The dry-bulb air temperature entering

and surrounding the unit shall be 80“F (26.7®C) and the wet-bulb temperature

5
entering the unit shall at no time exceed that value which results in the

production of condensate by the cooling coil at this test condition. The test

shall be conducted according to the test procedures outlined in section 3.2 for

steady-state tests. The duration of the test shall be a minimum of 1/2 hour.

The Low Temperature Cyclic Cooling Test (test L, section 2. 2. 3. 4) shall be

performed immediately following this test.

2. 2. 3. 3 Optional Test K, High Temperature Cyclic Cooling Test Conditions

The cyclic cooling performance test at a 70 “F (21.1“C) entering water temperature

shall be performed immediately following the steady-state High Temperature Dry

Coil Cooling Test (test I, section 2. 2.3.1). The steady-state test results and

the cyclic test results are used together to find the performance degradation

resulting from cyclic operation at high water temperatures. The water flow

rate during the on-period shall be the same as the rate during test I.

The dry-bulb and wet-bulb temperature of the air entering and surrounding the

unit shall be the same as test I. The cyclic performance test is conducted

according to the test procedures outlined in section 3.3.

During the cyclic test, the water flow and the indoor fan shall cycle ”on” and

"off” as the compressor cycles "on” and "off", except that the indoor fan

cycling times may be delayed due to controls that are normally Installed with

the unit. The compressor cycling times shall be 6 minutes "on" and 24 minutes

"off".

2. 2. 3. 4 Optional Test L, Low Temperature Cyclic Cooling Test Conditions

The low temperature cyclic cooling performance test shall be performed

immediately following the steady-state Low Temperature Dry-Coil Cooling Test

(test J, section 2. 2. 3. 2). The steady-state test results and the cyclic test

results are used together to find the performance degradation resulting from

cyclic operation at low water temperatures. The entering water temperature

and flow rate during the on-period shall be the same as that during test J.

The dry-bulb and wet-bulb temperature of the air entering and surrounding the

unit shall be the same as test J. The cyclic performance test is conducted

according to the test procedures outlined in section 3.3.

During the cyclic test, the water flow and the Indoor fan shall cycle "on" and

"off" as the compressor cycles "on" and "off", except that the indoor fan cyclic

times may be delayed due to controls that are normally installed with the unit.

The compressor cycling times shall be 6 minutes "on" and 24 minutes "off".

2.2.4

Conditions for Optional Cyclic Heating Tests

2. 2. 4.1 Optional Test M, High Temperature Cyclic Heating Test Conditions

The cyclic heating performance test at a 70“F (21.1“C) entering water

temperature shall be performed immediately following the steady-state High

Temperature Heating Test (test G, section 2. 2. 2. 3). The steady-state test

6
results and the cyclic test results are used together to find the performance

degradation resulting from cyclic operation at high water temperatures. The

water flow rate during the on-perlod shall be the same as for test G. The

dry-bulb and wet-bulb temperature of the air entering and surrounding the unit

shall also be the same as test G. The cyclic performance test is conducted

according to the test procedures outlined In section 3.3.

During the cyclic test, the water flow and indoor fan shall cycle "on" and

"off” as the compressor cycles "on" and "off", except that the Indoor fan

cycling times may be delayed due to controls that are normally installed with

the unit. The compressor cycling times shall be 6 minutes "on" and 24 minutes

"off".

2. 2. 4. 2 Optional Test N, Low Temperature Cyclic Heating Test Conditions

The low temperature cyclic heating performance test shall be performed

Immediately following the steady-state Low Temperature Heating Test (test H,

section 2. 2. 2.4). The steady-state test results and the cyclic test results

are used together to find the performance degradation resulting from cyclic

operation at low water temperatures. The entering water temperature and flow

rate during the on-period shall be the same as for test H. The dry-bulb and

wet-bulb temperature of the air entering and surrounding the unit shall also

be the same as test H. The cyclic performance test is conducted according to

the test procedures outlined In section 3.3.

During the cyclic test, the water flow and the Indoor fan cycle "on" and "off"

as the compressor cycles "on" and "off", except that the indoor fan cycling

times may be delayed due to controls that are normally Installed with the unit.

The compressor cycling times shall be 6 minutes "on" and 24 minutes "off".

7
3. HEAT PUMP PERF0PJ4ANCE TEST PROCEDURES

3.1 INTRODUCTION

The test procedures are categorized as follows:

Steady-State Test Procedure - section 3.2

Cyclic Test Procedure - section 3.3

The tests are designed to determine the performance of the heat pump unit tinder

conditions of typical use, as well as to establish a performance curve from

which the seasonal performance and cost of operation may be determined.

3.2 STEADY-STATE TEST PROCEDURE

3.2.1 Available Test Methods

Listed below and In the ASHRAE Standard 37-78 are the recommended test methods

for conducting steady-state tests of heat pumps.

1) Air Enthalpy Method - Indoor-Side

11) Water Coil Method - Outdoor-Side

ill) Compressor Calibration Method

iv) Volatile Refrigerant Flow Method

The Air Enthalpy Method - Indoor Side shall be used as the primary method for

all tests. In addition, one other method chosen from the above list shall

simultaneously be employed in tests E, F, G, and H as a check on the Air Enthalpy

Method - Indoor Side. The steady-state capacities, as measured by the two

methods and calculated according to the procedures outlined in ASHRAE Standard

37-78, shall agree within 6 percent in order to constitute a valid test. The

results of the Air Enthalpy Method - Indoor Side shall, however, be the only

results reported and utilized in the heating seasonal performance calculations

of section 4. Units containing the compressor located with the indoor section

and separately ventilated shall not use a test method which includes compressor

heat rejection in the determination of heating capacity.

Requirements to be followed in employing the various test methods listed above

as suitable for checking the results of the Air Enthalpy Method - Indoor Side are given in ASHRAE Standard 37-78 under the following sections.

Volatile Refrigerant Flow Method - section 5.1 - 5.5.1

Compressor Calibration Method - sections 4.1 - 4.6.1 except that

only 4 sets of reading are required in section 4.2.1

Outdoor Water Coil Method - sections 6.1 - 6.6.1

8
results and the cyclic test results are used together to find the performance

degradation resulting from cyclic operation at high water temperatures. The

water flow rate during the on-period shall be the same as for test G. The

dry-bulb and wet-bulb temperature of the air entering and surrounding the unit

shall also be the same as test G. The cyclic performance test is conducted

according to the test procedures outlined in section 3.3.

During the cyclic test, the water flow and indoor fan shall cycle "on" and

"off" as the compressor cycles "on" and "off", except that the Indoor fan

cycling times may be delayed due to controls that are normally installed with

the unit. The compressor cycling times shall be 6 minutes "on" and 24 minutes

"off".

2. 2. 4. 2 Optional Test N, Low Temperature Cyclic Heating Test Conditions

The low temperature cyclic heating performance test shall be performed

immediately following the steady-state Low Temperature Heating Test (test H,

section 2. 2. 2.4). The steady-state test results and the cyclic test results

are used together to find the performance degradation resulting from cyclic

operation at low water temperatures. The entering water temperature and flow

rate during the on-perlod shall be the same as for test H. The dry-bulb and

wet-bulb temperature of the air entering and surrounding the unit shall also

be the same as test H. The cyclic performance test is conducted according to

the test procedures outlined in section 3.3.

During the cyclic test, the water flow and the indoor fan cycle "on" and "off"

as the compressor cycles "on" and "off"

except that the Indoor fan cycling

times may be delayed due to controls that are normally Installed with the unit.

The compressor cycling times shall be 6 minutes "on" and 24 minutes "off".

7
3. HEAT PUMP PERFORMANCE TEST PROCEDURES

3.1 INTRODUCTION

The test procedures are categorized as follows:

Steady-State Test Procedure - section 3.2

Cyclic Test Procedure - section 3.3

The tests are designed to determine the performance of the heat pump unit under

conditions of typical use, as well as to establish a performance curve from

which the seasonal performance and cost of operation may be determined.

3.2 STEADY-STATE TEST PROCEDURE

3.2.1 Available Test Methods

Listed below and In the ASHRAE Standard 37-78 are the recommended test methods

for conducting steady-state tests of heat pumps.

1) Air Enthalpy Method - Indoor-Side

11) Water Coil Method - Outdoor-Side

ill) Compressor Calibration Method

iv) Volatile Refrigerant Flow Method

The Air Enthalpy Method - Indoor Side shall be used as the primary method for

all tests. In addition, one other method chosen from the above list shall

simultaneously be employed in tests E, F, G, and H as a check on the Air Enthalpy

Method - Indoor Side. The steady-state capacities, as measured by the two

methods and calculated according to the procedures outlined in ASHRAE Standard

37-78, shall agree within 6 percent in order to constitute a valid test. The

results of the Air Enthalpy Method - Indoor Side shall, however, be the only

results reported and utilized in the heating seasonal performance calculations

of section 4. Units containing the compressor located with the indoor section

and separately ventilated shall not use a test method which includes compressor

heat rejection in the determination of heating capacity.

Requirements to be followed in employing the various test methods listed above

as suitable for checking the results of the Air Enthalpy Method - Indoor Side are given in ASHRAE Standard 37-78 under the following sections.

Volatile Refrigerant Flow Method - section 5.1 - 5.5.1

Compressor Calibration Method - sections 4.1 - 4.6.1 except that

only 4 sets of reading are required in section 4.2.1

Outdoor Water Coil Method - sections 6.1 - 6.6.1

8
3.2.2 Air Flow Rate, Instrumentation and Data to be Recorded

Air Flow Rate

The indoor air flow rate shall be determined as described in sections 7.1

through 7.4.3 of ASHRAE Standard 37-78. In general, this requires the construction of an air receiving chamber and discharge chamber separated by a partition

in which one or more nozzles are located. The receiving chamber is connected

to the indoor air discharge side of the test specimen through a short plenum.

The exhaust side of the air flow rate measuring device contains an exhaust fan

with some means to vary its capacity to obtain the desired external resistance

to air flow rate. The exhaust side is then left open to the test room or is

ducted through a conditioning apparatus and then back to the test specimen

inlet

The static pressure across the nozzle(s), the velocity pressure, and static

pressure at the nozzle throat shall be measured with manometers which will

result in errors which are no greater than + 1 percent of the reading and

having minimum scale divisions not exceeding 2.0 percent of the reading or another measurement system of equivalent accuracy. Static pressure and temperature measurements must be taken at the nozzle throat in order to obtain

density of the air. The area(s) of the nozzle(s) shall be determined by

measuring their diameter with an error no greater than +0.2 percent. Four

measurements will be made approximately 45 degrees apart around the nozzle in

each of two planes through the nozzle throat, one plane at the outlet and the

other plane in the straight section near the radius.

Electrical Measurements

The electrical energy usage of the indoor fan shall be measured with a watt-hour meter which will result in an error which is no greater than +0.5

percent of the quantity of energy measured. Likewise, the energy usage of the

compressor and all other equipment components utilizing electrical energy shall

be measured with a watt-hour meter of the stated accuracy.

Indoor-Air Entering and Discharge Temperature

Measurements of the air temperature entering and leaving the Indoor coll or of

the difference between the entering and leaving temperatures shall be made in

accordance with the requirements of ASHRAE Standard 41.1-74 [5]. These temperatures shall be recorded at intervals of 5 minutes or less with instrumentation

having a total system error no greater than + .3®F (+ .17®C) and a response time

of 2.5 seconds or less in air at an average airspeed encountered in the region

of measurement. Response time is defined as the time required for the instrumentation to obtain 63 percent of the final steady-state temperature difference

when subjected to a step change in temperature of 15“F (8.3°C) or more. Temperature measurements are to be made upstream of the static pressure tap on the

inlet and downstream of the static pressure taps on the outlet.

9
Indoor-Side Ambient Conditions

The indoor-side dry-bulb temperature shall be recorded at Intervals

of 5 minutes or less with instrumentation which will result in an error no greater than + .3®F (+ .17®C).

Outdoor-Side Entering and Discharge Water Temperatures

The water temperatures entering and leaving the outdoor side heat exchanger and, if

the Outdoor Coil Method (section 3.2.1) is used, the difference between these

two temperatures shall be measured in accordance with the requirements of

ASHRAE Standard 41.1-7A using sheathed thermocouples inserted through pipe

plugs that are located within 12 inches (305 mm) of the inlet and outlet of

the unit. A minimum of 6 inches (152.4 mm) of sheathed thermocouple lead,

immediately upstream of the thermocouple junction, shall be Immersed in the

water between the pipe plug and the unit Inlet/outlet. The remainder of the

thermocouple lead shall be run along the surface of the pipe (and under any

insulation) for a distance of not less than 3 feet (183 mm). The pipe three

feet immediately before the inlet and three feet after the outlet shall be

covered with 0.5 inch (13 mm) of closed cell foam rubber insulation or equivalent. These temperatures shall be recorded with Instrumentation having a total

system error no greater than + 0.3“F (+ 0.17*C).

Liquid Flow Measurement

Liquid flow measurements shall be made in accordance with section 10.6 of

ASHRAE Standard 37-78.

Water and brine flow rates shall be measured with a liquid flow meter or quantity meter having an error no greater than +1.0 percent of the quantity

measured

Static Pressure Measurements in Ducts

Static pressure measurement in the ducts and across the unit shall be made in

accordance with section 8 of ASHRAE Standard 37-78 using a manometer which

will result in an error no greater than +0.01 Inches of water (+2.5 Pa) or another measurement system of equivalent accuracy.

Additional Instrumentation and Data Acquisition

Hand recorded data shall be taken at 5 minute Intervals. The data recording

interval for computerized data recording systems shall be 1 minute. Additional

requirements for instrumentation and data acquisition are listed in sections 10

and table II of ASHRAE Standard 37-78. Requirements for the Volatile Refrigerant Flow method are listed in section 5.2 through 5.5 of ASHRAE Standard 37-78.

Requirements for instrumentation when using the Outdoor Water Coil Method are

found in sections 6.2 and 6.6 of ASHRAE Standard 37-78.

10
3.2.3 Test Preparation and Performance

The equipment under test shall be Installed according to the requirements of

section 11.2 of ASHRAE Standard 37-78. Briefly, this requires that the unit

be Installed according to the manufacturer's Instructions, that no change in

external resistance to air flow to account for barometric changes should be

made, that pressure gages should be Installed with short lengths of small

diameter tubing, and that the unit is to be charged in accordance with the

manufacturer's recommended procedures.

Test chamber requirements are the same as given in section 11.1 of the ASHRAE

Standard 37-78. The test room apparatus and test specimens must be operated

for at least one hour with at least 1/2 hour at equilibrium and at the specified test conditions prior to starting the test. The steady-state test shall

then be conducted for a minimum of 1/2 hour with Intermittent data recorded at

10-minute intervals. The Air Enthalpy Method - Indoor Side shall be used along

with one other test method listed in section 3.2 conducted simultaneously. The

steady-state test may only begin when the test unit and room conditions are within the test conditions tolerances specified in section 3.2.4.

3.2.4 Test Tolerances

All steady-state tests shall be conducted within the tolerances specified in

table 3. Variation greater than those given in table 3 shall invalidate the

test. The heating capacity results by the Air Enthalpy Method-Indoor side shall

agree within 6 percent of the value determined by any other simultaneously

conducted capacity test in order for the test to be valid.

3.2.5 Data Analysis and Results

The results of the steady-state tests shall include:

• • i) Cooling capacity, Qgg c(70) and Qss,C^^®)* l^^®tu/h

• • ii) Dry coil cooling capacity, Qgg, dry, ^(70) and Qgg,dry,c(50) , kBtu/h

• • lii) Heating capacity, Qss,H^^®) ^Btu/h

• • iv) Electrical power input to all components,

Egg,dry,c(50) , Egg^jj(70), Egg^jj(50), kW

v) Indoor air flow rate (SCFM) and external resistance to indoor

air flow, inches of water

vl) Water flow rate, gpm

vil) Water pressure drop through the unit, psi

vlii) Indoor wet bulb temperature and indoor dry-bulb temperature, "F

11
ix) Data to be recorded as specified in table 11 of ASHRAE Standard 37-78

Only the capacity results obtained by the Air Enthalpy Method Indoor side shall

be reported and used in the calculation procedure described in section 4. The

steady-state dry coil cooling tests (test I and test J) may be omitted and a constant degradation factor assumed (table 2).

The formulae to be used in calculating the heating capacity and the indoor air

flow-rate are presented in sections 3.8.1 and 7.4 of ASHRAE Standard 37-78.

The coefficient of performance, COP, is defined as the ratio of the heating

capacity in kBtu/h to the product of 3.413 kBtu/h-kW (1000 W/kW) and the power

inputs to the indoor fan and other equipment components in kW. For heat pumps

units not having an indoor fan as part of the model tested, 1.250 kBtu/h per

1000 SCFM (7.77 watts per m^/s) of Indoor air handled shall be subtracted from

the measured cooling capacities to obtain the. total cooling capacities,

QSS.C(^O), Qss,dry,c(^0) , Qss.dry ,c(50) , and Qss,c(50), and 1.250 kBtu/h per

1000 SCFM (7.77 watts per m3/s) of indoor air shall be added to the measured

capacities to obtain the total heating capacities, Qgg ^(70) and Qgg g(50).

Also for the units not having an indoor fan as part of the model tested 0.365

kW per 1000 SCFM (7.77 watts per m^/s) of Indoor air handled shall be added to

the measured power to obtain the total po^^er Inputs to ^he unit,

ESS,C(50), EsS,dry,c(70)» Ess,dry,c(50) , Ess^h( 70) and Ess,h(50)*

For all units a penalty shall be added to the measured power input in the

amount of 60 watts/gpm of water, flow (951 w/£/s) to obtain the total power

inputs to the unit. Egg r(70). Egg r(50), Esg,dry ,C<70) , Egg dry,c(50),

Ess,h(TM). and Ess,h(505-

3.3 CYCLIC TEST PROCEDURE

3.3.1 Available Test Methods

The cyclic performance tests must be carried out immediately following the

steady-state tests at comparable conditions as described in section 2.2.2

through section 2.2.4. This is necessary since the results of both tests must

be used to determine the part load degradation coefficient, Cj), described in

section 3.3.5. The cyclic tests, comparable steady-state tests, and resulting

degradation coefficients may be summarized as follows:

Cyclic

Test

Follows

Comparable

Steady-State Test

Resulting in

Degradation

Coefficient

K, High Temp. Cyclic Cooling I, High Temp. Dry-Coil Cooling

M, High Temp. Cyclic Heating G, High Temp. Heating

L, Low Temp. Cyclic Cooling J, Low Temp. Dry-Coil Cooling

N, Low Temp. Cyclic Heating H, Low Temp. Heating

Cd,c(50)

Cd,H(70)

Cd,H(50)

12
The test method for measuring the capacity during the cyclic operation shall be

the Air Enthalpy Method Indoor side. No additional simultaneously conducted

test method need be employed since the cycling of the unit tends to invalidate

results of other test methods. Instead, it is assumed that the test setup and

instrumentation has been proven accurate by the requirement that the capacities

measured by the two test methods simultaneously employed in the steady-state

tests must agree within 6 percent.

3.3.2 Air Flow Rate, Instrumentation and Data to be Recorded

The air flow rate during the on-period of the cyclic test shall be the same (agree within + 1 percent) as the air flow rate measured during the previously

conducted steady-state test. Data to be recorded and instrumentation requirements are identical to the requirements of section 3.2 for steady-state tests

where applicable. The instrumentation required to record the air temperature

entering and leaving the Indoor portion of the unit or the difference between

these two temperatures shall have a response time of 2.5 seconds or less in air

at an average airspeed encountered in the region of measurement. (Response

time is defined as the time required for the Instrumentation to attain 63 percent of the final steady-state temperature difference when subjected to a step

change in temperature difference of 15®F or more). The electrical energy useage of the indoor fan and the energy usage of the remaining equipment components

shall be recorded with watt-hour meters.

If a data acquisition system is not used, data used in monitoring room control

shall be recorded at 5 minute intervals , and data used directly in calculations

shall be recorded continuously by a multi-pen recorder.

If a data acquisition system is used, data used in monitoring room control

shall be recorded at 20 second intervals, and data used in calculations shall be

recorded for the first minute after start-up, shut down, or fan delay, at an Interval of 5 seconds, for the second and third minutes thereafter at an interval of 10 seconds, and thereafter at an interval of 20 seconds. The

integration of temperature-time profiles should be the arithmetic average of the

current temperature value and the previous temperature value multiplied by

their respective time difference, and these products summed over the entire fan

on-period. Note that this discrete data recording scheme is not applicable to

electrical power measurements which still should be done with watt-hour meters.

3.3.3 Test Preparation and Performance

The test rooms and equipment installation requirements are identical to the

steady-state test procedures described in section 3.2.3. It is suggested,

however, that electric resistance heaters be Installed in the test room where

applicable and be cycled "on" when the unit is cycled "off", in order to reduce

the fluctuating heating and cooling loads imposed on the room reconditioning

equipment by the cycling of the test equipment. The heater should be approximately the same capacity as the heating capacity of the equipment under test.

During the cyclic tests, the water flow through the unit shall cycle "on" and

"off" as the compressor cycles "on" and "off". If the unit does not have an

13
Integral solenoid that accomplishes this purpose, such a solenoid must be added

to the water supply circuit. It is suggested that a solenoid controlled bypass

circuit be installed which will open when the unit cycles "off” to maintain a constant flow through the inlet water temperature control system. It is also

suggested that the water system be "total loss" (non-recirculating) to reduce

deviation of the inlet water temperature from the value measured during the

comparable steady-state test.

These suggestions are made in recognition of the fact that most water

temperature control systems will not be able to control within the test toler- ance required by this standard if either the water flow rate past the control

system temperature sensing element or the supply water temperature vary

excessively.

At the conclusion of the appropriate steady-state test, the unit shall be

manually cycled "off" and "on", using 24 minute "off" and 6 minute "on" time

periods until steadily repeating ambient conditions are achieved for both the

indoor and outdoor test chamber, but for not less than 2 complete "off "/"on"

cycles. Without a break in the cycling pattern, the unit shall be operated

through an additional "off "/"on" cycle, during which the required test data

shall be recorded. During the last cycle, which is referred to as the test

cycle, the indoor test room ambient conditions shall remain within the tolerance specified in section 3.3.4.

During the cyclic tests, the water flow and the indoor fan shall cycle "on" and

"off" as the compressor cycles "on" and "off" except that the indoor fan cycling

times (but not the water flow) may be delayed due to controls that are normally

installed with the unit. The test installation shall be designed such that

there will be no air flow through the unit due to natural or forced convection

while the fan is "off".

3.3.4 Test Tolerances

The test condition tolerances and test operating tolerances for the on-period

portion of the test cycle are specified in table 4. Variations exceeding any

specified test tolerance shall invalidate the test results.

3.3.5 Data Analyses and Results

The reuslts of the cyclic tests shall consist of the Degradation Coefficients,

^D,c(^0), Co^c(50), Cd^ji( 80) and Cd^h(50).

The actual heating or cooling done during the test cycle, Q^yc kBtu, shall

be determined using the following equation:

Qcyc(T) =

1 1000

(3.1)

(time, indoor fan off)

(3.2)

(time, indoof fan on)

14
and V Is the flow rate during the on-perlod as measured during the comparable

steady-state test and calculated in accordance with section 7.4 of ASHRAE

Standard 37-78.

For heat pump units without an indoor fan which are tested in the cyclic cooling

test (test K and test L), the cyclic capacity determined above, Q^y^(T), shall

be decreased by an amount equal to the product of 1.250 kBtu/h per 1000 SCFM

(7.77 watts per m^/s), the length of the on-period of the test cycle in hours,

and the flow rate of indoor air circulated in units of 1000 SCFM. For cyclic

heating tests (test M and test N) of units without an indoor fan the cyclic

capacity shall be increased by the same amount.

The total energy usage during the test cycle, E shall be the sum of the energy

usage required for air circulation during the telt cycle and the energy used by

the remaining equipment components during the test cycle. Units not having a fan as part of the model tested shall set the energy required for air circulation

equal^to the quantity given by the product of 0.365 kW per 1000 SCFM (J .11 Watts

per m Is) , the length of the on-period of the test cycle in hours and the rate

of indoor air circulated in units of 1000 SCFM. The energy required for water

circulation shall be set equal to the quantity given by the product of 60 watts

per gpm of water flow (951 w/l/s) measured at each test condition and the length

of the on-period cycle in hours.

The cyclic coefficient of performance, C0Pj,y(,, shall be the ratio of the total

heating or cooling done in kBtu (w) during the test cycle to the product of

3.413 kBtuh/Kw (1000 w/kW) and the total energy usage, in kW, during the test

cycle when the total heating or cooling done and total energy usage have been

adjusted as described above. The cyclic degradation coefficient for heating,

Cj),H» or cooling C]) c> shall be calculated as follows at the entering water

temperature of the test:

1 - COP

COP

m

SS'>^'' C = - D 1 - (HLF or CLF)

(3.3)

where HLF, CLF =

Q

Oss (T)

eye (T)

X (ton + toff)

(3.4)

Qss(T) and COPss(T) are the steady-state cooling or heating capacity (kBtu/h)

and coefficient or performance, respectively, determined from the steady-state

performance test (E, F, I or J) conducted at entering temperature, T, and ton

and toff are the "on" and "off" times during the test cycle, respectively, in

hours. The degradation coefficient, Cp, shall be reported to the nearest .02.

15
4. CALCULATION OF CSPF, HSPF AND SEASONAL COST OF OPERATION

4.1 DISCUSSION OF THE CALCULATION PROCEDURE FOR SHALLOW GROUND WATER SOURCE

APPLICATIONS

The temperature of shallow ground water in a particular location is determined

mainly by the mean annual air temperature of the region, and in most locations

ground-water temperature at a depth of 30 to 60 feet (9 to 18 meters) usually

remains constant within approximately one degree fahrenheit (0.6*C) during the

year. Due to these reasons, the entering water temperature in the calculation

procedure is assumed to be constant year round at an assigned value for each

major climatic region of the country.

The calculation procedures assume that a water source heat pximp will be sized

to meet either the design heating or cooling load. It is also assumed that

resistance heat will be provided to maintain conditions when the building

heating load is greater than the heat pump heating capacity.

Since the ratio of the house thermal gain factor (UA, Btu/h®F, W/*C) during the

cooling season to the loss factor during the heating season will have a range

of from nearly unity to approximately two, it is recommended that for each

design load (heating or cooling), a range of seasonal performance factors be

calculated corresponding to the range of possible ratios of thermal loss and

gain factors between seasons.

Six climatic regions of the U.S. are identified for use in performance factor

calculations. Figure 1 is a map of heating load hours (HLH) for the continental United States that defines the six regions for which seasonal bln calculations are to be performed. Figures 2 and 3 are maps of cooling load hours

(CLH) and ground water temperatures, respectively, which may be useful in

estimating the performance of a heat pump at a specific location. The typical

performance calculations for entry in table 9 are to be performed using the

cooling load hours and ground water temperatures listed in table 5; figures 2

and 3 are not to be used for this purpose.

The seasonal performance factors are to be calculated by the bin method. A

single set of bins is to be used in all regions for the cooling season (see figure

6). Two sets of bins are to be used for heating seasonal calculations, one for

climatic regions I through V and a second for region VI (see table 7). The

additional set of bins for region VI is provided because of the atypical

temnerature bin - hour distribution in this region.

4.2 CALCULATING CSPF, HSPF AND SEASONAL OPERATING COST FOR GROUND WATER

SOURCE HEAT PUMP APPLICATIONS

Table 5 lists the cooling load hours, heating load hours, heating outdoor design

temperatures and design ground water temperatures required in the performance

factor calculations for each of the six major U.S. climatic regions. Table 6

lists the fractional hours in each temperature bin for the single set of cooling

bins and table 7 lists the fractional hours in each temperature bin for the two

sets of heating bins.

16
In order to evaluate the seasonal unit performance in each region, its full

load, steady-state heating and cooling capacities, and coefficients of performance at the water temperature for the region must be known. Laboratory tests

have shown that these quantities are approximately a linear function of the mean

water temperature, the average of the water temperature in and out of the unit.

Since the capacity is linear with mean water temperature, for a unit with a constant water flow the difference between the entering water temperature and

mean water temperature will be linear with either of these temperatures. Consequently the capacity and COP will be linear with entering water temperature for

a constant water flow application. In such cases, the heating and cooling capacities and coefficients of performance for a specific entering water temperature

shall be calculated for the seasonal performance calculations using the following

equations

Qss,c^^Q^ ~ Qss,c(^Q)

20

(T - 50) (4.1)

COPSS.C(T) “ COPgs_(.(50) -

ggP

.SS,c(50) -^C0Pss,c(70)

- QsS,h( 50) +

’iSS,H(70) -^QsS.h(SO)

^^ _

C0Pss,h(t) = COPss,h(50) + 9P^ss,h(7°)

~

- 50)

and E(T) Q(T)

3.413 COP(T)

(4.2)

(4.3)

(4.4)

(4.5)

If the water flow rate is not constant but is a known non-linear function of

temperature, the data shall be Interpolated or extrapolated as required using

the following equations:

^SS,c(^m) " QSS,C^^®^

Tm,c<70) - T^,e(50)

(Tm - T„,c(50)) (4.6)

COPoq r(50) - COPqq p(70)

“fss.c^v “ COPgg ^(50) - (In, - T„ ,,(50)) ss,c

Tni.c<70) - T„ ^(50) "m '•m.c’ m.c

QsS,H(Tm) = QsS,h(^0) Qss.h(50) - Qss.h(70)

Tm,h(70) - T^,h(50)

* / c

fv \ C^m ” ’^m,h(^®))

COPsS,HCTni) = COPss^hCSO)

where:

2m Ti + ar ^ 33 I "“•<= 2& - b.

C0Pss.k(50) - 00Pss,h(70),„ „ ~ - T„.b(30)

(4.7)

(4.8)

(4.9)

(4.10)

17
2mTi-ai^ " 2m +

(4.11)

and:

^c “ Qss,c(^®) ^ Tto^c(70) (4.12)

(4.13)

^h = QsS,h(70) “ ^ (4.14)

, Qss.h(70) - Qss.h(50) (4.15)

where: = Mean (Average) water temperature through the unit, ®F (®C)

= Inlet water temperature, ®F (®C)

m = Water flow rate, Ibs/h

Tm,c(70) = Tm at test condition I

Tm,c(50) = Tia at test condition J

Tni,h(70) = Tnj at test condition G

Tm,h(50) =* Tm at test condition H

If these non-linear flow equations are us?d, the value of m used in making the

pump power correction (Section 3.2.5) on Q and COP values shall be that which

is used in these non-linear flow equations instead of the actual test values.

When a heat pump is sized to meet either the design cooling or design heating

load, the minimum and maximum loads to be met in the other non-design season

will depend upon the range of the ratio of the building summer heat gain factor

to the building winter heat loss factor. To account for this, it is recommended

that the seasonal performance and cost of operation be calculated for a number

of design loads between minimum and maximum load values determined as follows:

Maximum design cooling load

Minimum design cooling load

(Regions I, II, III, IV,

Minimum design cooling load

(Region V)

~ Qss,c

= The lesser of Qss,H or

VI). 2(65®F-Tod)

‘ss ,c

= The lesser of Qss,H or Qss,c

2.2

Maximum design heating load =» The greater of ^ Qsf

(Regions I, II, III, IV, VI) 60

(65®F - Tqjj) or Q‘ss,H

(4.16)

(4.17)

(4.18)

(4.19)

18
Maximum design heating load =« The greater of 2.2Qss,c or Qss,H (4.20)

(Region V)

Minimum design heating load = The lesser of Qss ,c (65®? - Tqjj) or Qss»H (4.21)

(Regions I, II, III, IV, VI) 60

Minimum design heating load = The lesser of Qss,c or Qss,H (4.22)

(Region V)

Where Qgg ^ and Qgg jj are the steady-state cooling and heating capacity,

respectively* calculated at the regional water temperature given in table 5.

Tqd is the outdoor design temperature given in table 5.

The above calculated maximum and minimum design loads are to be rounded to the

nearest standardized value from table 8.

The seasonal performance factors, CSPF and HSPF, are to be calculated by the

bln method at the maximum and minimum design loads and at all standard design

loads from table 8 between the maxlmxim and mlnlmtim loads.

For each climatic region and for design heating and cooling loads for which

bln method calculations are required, the heating seasonal performance factor,

HSPF, cooling seasonal performance factor, CSPF, and seasonal operating cost of

a heat pump shall be determined using:

HSPF

‘j BL, N "^H

(3.413) 5J N

W

PLFjj(X) ^H

RH(Tj)

N

(4.23)

Heating

Seasonal = (HLH) (C) (Design Heating Requirements) (Cost per kWh in $*s), (4,24)

Operating (3.413)(HSPF)

Cost

CSPF

BL* (Tj)

(3.413) I

J N PLF^(X)

(4.25)

Cooling

Seasonal _ (CLH) (C) (Design Cooling Requirements) (Cost per kWh in $*s) , (4.26)

Operating (3.413)(CSPF)

Cost

BLc(Tj)^ BL(Tj) < Qgg^c

Where BL$(Tj) = ( .Qss,c, BL(Tj) > Qss,c

19
j = 1, 2, 3, , n corresponds to the j^h temperature bin

n total number of non-zero temperature bins in the climatic region

Tj for heating = (67 - 5j)

Tj for cooling = (62 + 5j)

Ej indicates the quantity following the symbol is to be summed over all

temperature bins, starting with j

** 1 RH(Tj)

_ supplementary resistance heat term at temperature Tj required when

N It Is needed to meet the balance of the building heating requirements,

(kW)

j Is the number of hours In the temperature bln divided by N=Ejnj

N and is referred to as the "fractional hours In temperature bin’'

HLH * Is the number of heating load hours for the region as given In table 5

CLH = Is the number of heating load hours for the region as given in table 5

DHR = Is the design heating requirement (kBtu/h)

DCR = is the design cooling requirement (kBtu/h)

3.413 = is a conversion factor which converts kilowatt hours to kBtu

Tqd * is the outdoor design heating temperature given in table 5 for each

major climatic region, (*F)

C = 0.77 is an experience factor which tends to improve the agreement between

calculated and measured building loads

BL(Tj) = building load at temperature Tj, (kBtu/h)

X(Tj) = heat pump load factor

PLF(X) = heat pump part load factor

The quantities BL(Tj), X(Tj), PLF(X) and are defined by the following

equations; N

BLii(Tj) =

BL^(Tj) =

65 - T

” ^OD

Tj - 65

(1.1) (30)

L (C) (DHR)

(DCR)

(4.27)

(4.28)

20
for either ) Q

\ ^ss

heating or i cooling I 1 ;

; Q33 > bl(t.)

Qss 1 BL(Tj) (4.29)

PLF(X) = 1 - Cd( 1 - X(Tj))„ (4.30)

for either

heating

or cooling

RH(Tj)

N

BLh(Tj) - Qgg nj

3.413 N*

BLjj(Tj) > Q8S (4.31)

It should be noted that if the quantity Q(T) . is less than unity

(3.413)(E(T))

the value of E(T) used in the above HSPF calculation should be set equal to

Q(T)/3.413 at this particular temperature T,. This is done to avoid the possibility that any errors, introduced by the straight line extrapolation of the

measured capacities and power inputs could cause the heat pump to have a COP

which is less than unity.

A sample calculation showing the use of these equations is given in appendix A

as an aid to their application in the calculation of heating and cooling seasonal

performance factors and seasonal operating costs for each of the six regions

specified in table 5. Once the maximum. Intermediate and minimum design heating

and cooling requirements, HSPF, CSPF, and corresponding operating cost values

have been obtained for each standardized design requirement (see tables 5, 8)

in each region, it is recommended that all seasonal operating cost figures be

rounded off to the nearest five dollars and the information be arranged in a form similar to table 9 to assist the consumer in selecting the most costeffective heating appliance for his residence.

21
REFERENCES

1. Air Conditioning and Refrigeration Institute Standard 325-82, "Ground Water

Source Heat Pumps."

2. American Society of Heating, Refrigeration and Air Conditioning Engineers

Standard 37-1978, "Methods of Testing for Rating Unitary Air Conditioning

and Heat Pump Equipment."

3. G. E. Kelly, W. H. Parken Jr., "Method of Testing, Rating and Estimating

the Seasonal Performance of Central Air Conditioners and Heat Pumps

Operating In the Cooling Mode," NBSIR 77-1271.

4. Walter H. Parken, George E. Kelly, and David A. Dldlon, "Method of Testing,

Rating and Estimating the Heating Seasonal Performance of Heat Pumps,"

NBSIR 80-2002.

5. American Society of Heating, Refrigeration, and Air Conditioning Engineers

Standard 41.1-1974, "ASHRAE Standard Measurement Guide: Section on Temperature Measurement."

22
Table

1.

Summary

of

Test

Conditions

n 9

4) T3 H 4) rJrg <MC«4 <NP'] cnf^ cor^

eo o 5 S

u •

4) u a 4J 8 e < V

b3 H

i-4 <NCO >^ r-< P‘Jr-)>^ r^cg CNC'iCS <NfO <nrOfn -.»^'*^-

C^lCvICMCSC'lfMCJCMC^CM

<NCMrgcNCMCvir^ cM<NCJ ^ »—

^ ^ ^ 1^ ^ ^

C'JCNCNCMPOC'JCNlCvlfMCNJ P4CNC'4CNjeMC'J <MrJf'4CvJ

II

I I

X X Ojwww'.-'ffl co BE BE

s : B C O C

(0 co (0 (Q n) tO 4J 4J 4J ^ 4J 4-> w Vi v> Vi t/i w

t I I I I t S s X >» X >» >> >>

<0 *B *0 *0 *B*0 B d

qjfl) (Odd d *H "^

4> 4) Vdd 4) S 0

4J 4J 4J 4J 4J <J I I ViViViViViVi^\o f f

vC sD 4) (0

«J t4

u X U X o cc

4J AJ 4J 4J 4J

0) CO 0) (0 00 0) 4) 4) 4) V d 4) HHHHHH

C B 6 B B B ^ ^ *o ^ ^ *d

4) 4) d 4) 4) V

« CO d CO (0 CO CO 13 3 3 9 9 9

00 CD CO CD CO 00

<B cQ d CO <9 C9

4) 4) 4) 4) 41 4> e 8 i e i e d d d d d d

cn c/2 W c/5 c/5 CO

d u

j=

(0 4) X ,J 4J •o X

DO 5^.

60 O

*0 B O O I

4J B

O U *H O *J

C./ • 9 AJ

4) »0 *H ^ O B 9^9 4J O* d 4) Vi 41

4) ^ AJ O. AJ § B ^

4) a

a: 8

4)

, Q> H I

I 9 £

d AJ d AJ 60_

d ^ d *H

(u d u a: 6. 4> o. 4> 8 Ck. 8 B.

4) 8 4) 8 *H H 4» H 4> O H HO X X

60 ^ 60 ^ X

•H O iJ O L X s: ^ o

o. u

8 4) 4) ki 4> H 9 Vi AJ 9

3 d AJ o ki d

1-3 4) w a 4)

r-A 8 O.

•rA 4) 8 O H 4> U H

X O U X

o

4> Ad 41 9 Vi AJ 9

8 a

4> 8 H 4) X 60 ^ 60 ^

X CO 4)

•H *H X

CD X AJ

. & - t ^ U4 ^ ^

. 4) AJ 60 O

AJ d B

d B Vi -H ^ d 4) AJ o a (A

4) 8 -H

•-) X as z

4) X

d COQOCOCncOtOCOQOCOCO dddddddddd HHHHHHHHHH

23
Table 2. Cyclic Test Options

1) Perform Tests I, J, K, L, M, N.

2) Perform Tests I and K, assume constant cooling Cp q at value given by Tests

I and K perform Test N, assume constant heating at value given by

Tests H and N.

3) Assume constant cooling C]) » 0.25. Perform Test N» assume constant

heating at value given by Test H and N.

A) Omit Tests I, J, L» M, N, assume constant Cq == 0.23.

2A
Table 3. Steady-State Test Tolerance for Tests E, F, G, H, I, J

Test Operating Test Condition

Tolerance* Tolerance**

Indoor dry-bulb, ®F

Entering 2.0 0.5

Leaving 2.0 —

Indoor wet-bulb, *F

Entering 1.0 0.3

Leaving 1.0

Outdoor water, *F

Entering 0.5 0.2

Leaving 0.5 —

Water flow, % 2 -

External resistance to 0.05 0.02

air flow. Inches of water

Electrical voltage, % 2.0 -

* Test Operating Tolerance is the maximum permissible variation of any

measurement. When expressed as a percentage > the maximum allowable

variation is the specified percentage of the average value.

** Test Condition Tolerance is the maximum permissible variation of the

average value of the measurement from the standard or desired test

condition.

25
Table 4. Test Tolerances for the On-Period Portion of Cyclic Performance

Tests, K, L, M, and N

Test Operating Tolerance*

(Applies after the 1®*- 30 sec. Test Condition

after compressor start-up Tolerance**

Indoor dry-bulb, *F

Entering

Leaving

Indoor wet-bulb, *F

Entering

Leaving

Outdoor water, ®F

Entering

Leaving

Water flow, %

2.0

1.0

0.5

2

External resistance to 0.05

air flow. Inches of water

Electrical voltage, % 2.0

0.5

0.2

0.02

* Test Operating Tolerance is the maximum permissible variation of any

measurement. When expressed as a percentage, the maximum allowable

variation is specified percentage of the average value.

** Test Condition Tolerance is the maximum permissible variation of the

average value of the measurement from the standard or desired test

condition.

26
Table 5. Design Conditions for Six Standardized Climatic Regions

Region CLH HLH ^0D,H

I 2400 750 37 72

II 1800 1250 ^ 27 68

III 1200 1750 17 62

IV 800 2250 5 53

V 400 2750 -10 45

VI 200 2750 30 55

27
Table 6. Fractional Temperature Bin Hours for Cooling Season Calculation

Bln No.

j

1

2

3

4

5

6

7

8

Bln Temp •

Tj. "F

67

72

77

82

87

92

97

102

Fraction of Total

Temperature Bln Hours

nj/N

0.214

0.231

0.216

0.161

0.104

0.052

0.018

0.004

28
j

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

Fractional Temperature Bln Hours for Heating Season Calculations

Region I - V Region VI

Bln Temp.

Tj, “F

Fraction of Total

Temperature Bln Hours

Uj/N

Fraction of Total

Temperature Bln Hours

nj/N

62 0.132 0.113

57 0.111 0.206

52 0.103 0.215

47 0.093 0.204

42 0.100 0.141

37 0.109 0.076

32 0.126 0.034

27 0.087 0.008

22 0.055 0.003

17 0.036 0

12 0.026 0

7 0.013 0

2 0.006 0

-3 0.002 0

-8 0.001 0

29
Table 8. Standardized Design Heating and Cooling Requirement Values (kBtu/h)

5 25

10 30

15 35

20 40

50 90

60 100

70 110

80 130

30
Table

9.

Example

of

Information

Which

Would

Assist

A

Consumer

In

Purchasing

A

Heat

Pump

e

o

COC4

<U CO

C>0 e

•H

4J

CO

(U s

COoo

bOc

•H

4-1 COV

o. o

<u3

a

bO 0) c c e

bO -*-1 0» •H -U U

CO CO <U 0) 3 Q 3J crm

oi

U1 O LTi O o o o CM PI cn in vo

a —

o •

0)

cQ0) N CO JS 00 3 O

bO JkS • c

•H </> O

o iH O

o 01 • d aU o o

CO • o 4J o COo

taO CJ (N a O •H • 4J

cd

1-1 <va CO o CJ

u

G

no Q) jc c c e

bO p-l m 3

•H f—C Ul

CO O "H (O V o n M

Q O C7* —

(V ai

m o o o o PI -a- m vo p>"

o

m

* a

H-l hJ a u o o

m o

o

o

<t

pj

o o o o o •9' in 'O tp. 00

o

in

533 u

o o m o00

o o o o o o o iT> vO 00 ON o

m o o ro <r m

a u

o o m

CM

rMooONO-HP^inr^ oooooooo

in o in o o o CM cn cn -jr in vo

o o

> m o M CM 00

CM

o m o o o cn cn sr in vo

inomoinooo —icMcMcncn-a-invo

a a

* o o

> in o<•

CM

O O m lo

a a j j

a u

o o

M -a- o

> CM

CM

Manufacturers

must

state

that

"This

heat

pump

is

not

recommended

for

use

in

this

region"

or

some

equivalent

phase

for

all

regions

in

which

the

ground

water

temperature

as

defined

in

Table

5

in

below

the

minimum

entering

water

temperature

at

which

the

manufacturer

recommends

application.
2500

3000 \

2500

3000 oom

CO

O

(0 •o u C *H

(0 t-i o

(0 *H 4J ^ *H *H

Oi tiU

(d > >-i iH (0 0) C EC H

0) J=

0)N

•H

iJ Wi

l-i 0>

(d c a 0)

t)0

(0

CD to O pH B jn

to o j:

MH

0) rH U *H

Cdh

(d

COCOV

CO CJ0) to C

43 CO

CO *H CO w

CO 3

cd JO

(UtJ COcu

CO 4-> •H Cd u

Q. CO

cdg T3

0)

CO 4J

•H *H c01c

•H CDU

(U •H

ti

Cd CJ ^ 5 3 PtS CJo QJ

CO 4=

JJ oo c

4J ft

•uO pH C

Cd to pH pH 3

4J CJ C *H

0) -U 3 U

cr td

oja

CO3 CO O 3 o o

•H *3 bO 3 OJ 3 l-i

4-1 33 o o o o o o m m m m m m t'»cMr>>cMr>.r'.

pH pH CM CM CM

32 330

•H003

01 30

•H003

01

MM > H

MM

M > >

Figure

1.

Actual

heating

load

hours

(HLH^)

and

regional

heating

load

hours

for

the

United

States
13 bO

•H

CC 4J -H -H a 4-> 0) (0 bO

fl

M fl •H QJ *H a. -M O

4Jaoo

4-)

M(1) O.o

ta

tio

CO CD

cd o.

(U

g

CO 9

4-) cd0)

x: <u bO9 4J oM bo jd X3 C

4J *H "9

4J 9

CO «d td V4 a 9 *H CO O 4J »-• ^ (0 9

(V

C

T>O

Cd 9 *H O *H 4J iH *H •9 -9

bO 9 9 9 9 0

•H 9 9 O 9 O 43 O O

<4-4 4J O

CO 9 9 O 4J •H cd 4J 4J 9 CO 43

•H '9 M 9

4-t 44

CO T-( t4 9 Q 95

Cd •9

-H T>

Cd oa

bO9

M-l

O o oo

44

CD 9 O 43 U 44

CM9

»49

bO

•H 99V49

<4-1 9

Pi

33
34

"Contributions

to

the

Hydrology

of

the

United

States,

1923-1924,'

Nathan

C.

Grover,

Ed.,

Water

Supply

Paper

520-F,

Temperature

of

water

available

for

industrial

use

in

the

United

States,

by

W.D.

Collins;

Department

of

the

Interior,

U.S.

Geological

Survey

Washington,

D.C.

,

1925
APPENDIX A

SAMPLE CALCULATIONS

The following sample calculations Illustrate the type of experimental data

required and the use of the formulas and tables presented to calculate the

CSPF, HSPF and seasonal cost of operation for different regions of the United

States. The heat pump performance data used to Illustrate the calculation

procedure are fictional and are not meant to be representative of typical or desired operational characteristics.

Experimental data which would result from the recommended test procedures is

presented in table Al for the fictitious heat pump. It is assumed that the

manufacturer has chosen the option of using a value of 0.25 for the cooling

degradation factor, C and a measured value of the heating C of 0.16.

(It should be noted tndt the manfacturer has the option of choosing any of

several combinations of assigned and measured C as given in section 2 . 2 .)

If this heat pump does not have sufficient heating capacity to meet the

Imposed building heating load, at any time, auxiliary electric resistance

heaters will supply the balance of the heating requirements.

Tables A2 and A3 are sample worksheets used to evaluate the CSPF, HSPF and

seasonal cost of operation. In this example, the CSPF, HSPF and operating cost

will be evaluated for a geographic location encompassed by Region IV (see table

5 and figure 1).

The design conditions for region IV given in table 5 are;

Cooling Load Hours , CLH: 800

Heating Load Hours, HLH; 2250

Temp., Outdoor Design, Heating, Tqd h*

Ground-Water-Temperature, T^ * 53®F

The heating and cooling capacity and COP at this ground-water-temperature are

by interpolation from the data given in table Al.

Qss,c<53) = 57.72 - ^iZl72_i_47^)(53 _ 5 Q) ^ kBtu/h (4.1)

COP (53) = 3.16 - ( 3.16 - 2.30)(S3 - 50) = 3.031 (4.2)

ss,c (70 - 50)

Qss,h(53) = 48.40 + (Z1i|0_2_48^)(53 _ 50^ ^ 52.50 kBtu/h (4.3)

COP ^(53) = 2.88 - ( _3»21 - 2. 88 )^ 5 ^ _ 50) = 2.930 (4.4) ss,H (70 - 50)

And;

A-1
g (53) (4.5) = 52 » 50

ss,c^ (3.413K3.031)

= 5.427 kW

E (53) — 52.50

(3.413)(3.031)

= 5.250 kW (4.6)

The maximum design cooling load for which a bin calculation is to be performed

is evaluated by equation (4.16) and is equal to the unit cooling capacity = 56.14 kBtu/h.

The minimum design cooling load for which a bin calculation is to be performed

is evaluated by equation (4.17^ as equal to the lesser of the unit cooling

capacity = 56.14 kBtu/h or 60 Qgg t2(65-ToD)

“ [(60)(52.50)]/[(2)(60)J = 26.25 kBtu/h.

The maximum design heating load for which a bin calculation is to be performed

is evaluated by equation (4.18) as equal to the greater of the unit capacity = 52.50 kBtu/h or [ (2) (Qgg ,c> <^5 - Tod)J/ 60 = [(2)(56.14)(60)]/60 * 112.28 kBtu/h.

The minimum design heating load for which a bin calculation is to be performed

is evaluated by equation (4.20) as equal to the lesser of the unit capacity = 52.50 kBtu/h or [Qgg^c^(^^ ~ Tod) 1/60 « [(56.4)(60)]/60 =* 56.14 kBtu/h.

The above values are rounded to the nearest Standardized Design Requirements

from table 8 below. Bin calculations of the CSPF, HSPF and seasonal cost are required at the maximum and minimum and Intermediate Standardized Design

Requirements from table 8 as follows:

Maximum standardized design cooling load: 60 kBtu/h

50 kBtu/h

40 kBtu/h

35 kBtu/h

30 kBtu/h

Minimum standardized design cooling load: 25 kBtu/h

Maximum standardized design heating load: 110 kBtu/h

110 kBtu/h

90 kBtu/h

80 kBtu/h

70 kBtu/h

60 kBtu/h

Minimum standardized design heating load: 50 kBtu/h

In this example, the bin calculations will be carried through only for the

maximum standardized design cooling and heating loads of 60 kBtu/h and 110

kBtu/h respectively.

In the following sample, heating and cooling season calculations for comparable

quantities are shown together to emphasize the differences and similarities

between the procedures for the two seasons. To the extent possible, the same column numbers are used for similar columns between the sample cooling seasonal

A-2
performance factor worksheet, table A2, and the sample heating seasonal

performance factor worksheet, table A3. In the sample calculations the subscript C is used to denote quantities being calculated for the cooling season

and the subscript H to denote those being calculated for the heating season.

The identification numbers of the equations from the test procedure are indicated in parentheses for each calculation.

Column d; Building Load

The building load is calculated for ecah representative outdoor temperature,

Tj , by equation (4.27) for heating and (4.28) for cooling.

Example ; Tj = 42°F

65 - T.

BLjj(42) = ____i(C)(DHR)

60

= §A-_^-?.(.77)(110)

60

= 32.468(kBtu/h)

Tj = 82°F

= (60)

(1.1)(30)

= 30.909(kBtu/h)

Column e; Load Factor

The load factor, X(Tj), is evaluated by equation (4.29) using the values from

columns (d) and the steady-state capacity, Qgs,c Qss,H*

Example ; Tj = 42°F for heating season

X„(42) = = 32.468 = .513

Tj = 82°F for cooling season

Xp(82) = ,

_ BL^(82)

_ 30.909 _

<ss ,c 56.14

= .551

The load factor for both heating and cooling has a maximum value of 1

A-3
Column f : Part Load Factor

The part load factor PLF(X) Is evaluated by applying equation (4.30), the data

from table Al, and values from column (e)«

Example ; Tj = 47 *F

PLFh(X) = 1 - Cd(1 - X(Tj))

= 1 - 0.16 [1 - .484] = .917

Example ; Tj ® 87 “F

PLF^CX) = 1 - 0.25 [1 - 0.7/13] - .928

Column g; Electrical Energy Input

The heat pump electrical energy Input for each temperature bln, j. Is represented

by the terms within the first summation sign In the denominator of equation

(4.23), re-wrltten here for convenience; /

nj X(Tj)(Ess)

N PLF(X)

Using table A2, the above expression may be evaluated as follows;

^ ^ (Col. c)(Col. e)(Egg)

(Col. g) = ———— Si-

(Col. f)

Example ; Tj = 12®F

(Col. g>H = (.026)(1)(5.250) » .1365

Example ; Tj = 82®F

(Col. g) = (.161)(.551)(5.427) = .5422

c (.888)

Column h (Table A3); Supplementary Resistance Heat

The supplementary resistance heat, ^

, is evaluated by using equation (4.32).

N

Example ; Tj = 12*F

RH(12) ^ [BL(12) - Qgg] ^

N 3.413 N

74.818 - 52.50 (0.026)

3.413

» .1700

A-4
Column h (Table A2); Cooling Load

The cooling load at each temperature bin, j, is represented by the term^within

the summation sign in the nimerator of equation (4.25, written as ^ BL^(Tj)

with a maximum value of _). , , a , , N

N

*

Example ; Tj = 87®F .

BLj,(Tj) = 40.000 < Qss,c “ 56.14

^

BL* (T.) = (0.104K40.000) * 4.1600

N J

Example ; Tj = 97®F . ...

;

BL(,(Tj) = 58.182 > Qss,c = 56.14

^ %s.c ‘ (56.14) . 1.0105

Column 1 (Table A3) ; Heating Load

The heating load at each temperature bin, j , is represented by the term within

the summation sign in the numerator of equation 4.23 written as ^ BLjj(T.).

N

'*

Example ; Tj = 12*'F

(Col. i) = (Col. c)(Col. d) = (.026K74.818) = 1.94533 [kBtu/h]

CSPF and HSPF

Equation 4.25 is evaluated for the CSPF and equation 4.23 for the HSPF using

the summation of the values in columns (g), (h), and (i) of tables A2 and A3.

Thus

CSPF =

Z

j

3.413[^ Col

j

21.3551

3.413 [2.3378]

2.68

And

HSPF j

Col. iy

3.413[2 Col. g„ + £ Col. h„]

j “ j “

33.7774

3.413 [3.2564 + .7086]

2.50

The seasonal operating costs are calculated by using equations 4.26 and 4.24.

Continuing the example, if the cost of electricity is assumed to be $.04/kWh

A-5
then the cooling seasonal operating cost Is approximately $210 and the heating

seasonal operating cost Is approximately $893.

The CSPF, HSPF and operating cost for geographic region IV has been calculated

In the above example for maximum design heating and cooling requirements. In

order to determine the range of seasonal performance and operating cost values

for the unit within the same region IV, the above CSPF, HSPF and cost calculation sequence should be repeated using the minimum and Intermediate design

requirements as previously discussed. Also, for each value of design requirement, a range of fuel costs should be used to produce a series of seasonal

heating and cooling costs.

The complete set of calculated data for the fictitious heat pump operating In

region IV Is given In table A4. Similar sets of data should be produced for

each region where It Is appropriate to operate the unit under test.

A-6
Table Al. Sample Data Required to Calculate the CSPF and HSPF for a Heat Pump

Sample Value*

Qss,c(70), kBtu/h 47.30

Qgg^c(^^)» kBtu/h 57.70

Qss,h( 70), kBtu/h 70.00

Qss^h( 50), kBtu/h 48.40

C0Pss,cC70) 2.30

COPss,c(50) 3.16

COPss.h(70) ' 3.21

COPss,h(50) 2.88

Degradation Factor, 0.25

Degradation Factor, - 0.16

* Sample values do not represent any particular heat pump unit.

A-7
Table A2. Sample Worksheet Used to Evaluate the CSFF and Seasonal Cost of

Operation

column (a) (b) (c) (d)

CO

l-l 3oX

0) H c

> •H •H •> 4-1 (U PQ M eg ^ rH

Q) *J 9 CO c c

G <u (d 0

9 CO >-< •H

2= cu cu 4J C S-i- o

CO •H CD IV l-l * Ui H c

X

9

4-1 9

H

n

(e) (f)

•* -O X cd i3 II 60/-N c •a O y-s O U O

1 67 0.214 3.636 .065 .766 .0986 .7782

2 72 0.231 12.727 .227 .807 .3523 2.9400

3 77 0.216 21.818 .389 .847 .5378 3.7127

4 82 0.161 30.909 .551 .888 .5422 4.9764

5 87 0.104 40.000 .713 .928 .4333 4.1600

6 92 0.052 49.091 .874 .969 .2548 2.5527

7 97 0.018 58.182 1 1 .0977 1.0105

8 102 0.004 67.273 1 1 .0217 .2246

2.3384 21.3551 Totals

Region (1, II, III, IV, V, VI). ^

Cooling Load Hours. 800 (hrs)

Regional Outdoor Temperature. ^ (“F)

/ / Minimum / / Maximum

Design Cooling Requirement. ^ (kBtu/h)

21.3551

CSPF » 2.68

(2.3384 K3.413)

(800)(60)(.04)

Seasonal Operating Cost = —~ = $210

(2.68X3.413)

A-8
Table Al. Sample Data Required to Calculate the CSPF and HSPF for a Heat Pump

Sample Value*

47.30

kBtu/h 57.70

Qss,h( 70)» kBtu/h 70.00

Qgg^H^^O)* kBtu/h 48.40

C0Pgs^c(70) 2.30

COPgg^c(50) 3.16

COPss,h(70)

- ^ ^^21

COPss,h(50) - 2.88

Degradation Factor, 0.25

Degradation Factor, 0.16

* Sample values do not represent any particular heat pump unit.

A-7
Table A2. Sample Worksheet Used Co Evaluate the CSPF and Seasonal Cost of

Operation

column (a)

*-)

(U JDz

c

•H

03

(b) (c) (d)

>(0M

o 9O

S3 •n

(1) H C

> •H

•H •' 4J 01 «

a M iH

4J 9 fl) C c

(U ig o

tn u •H

(U 01 U

U D. U

cu S m

lU 0) wi • OC H c

j:9

4J 9

H

•-)

(fl

(e) (f) (g) (h) —

60

tH 'w' « /-V II 0 u :z

•rl ^ \ u

(-1 w <4-1 s 4J w

y

OJ . /-V •H 4J W •9 ^

U 9 CO BJ V-/ o«u a c iS II 9 60^

Pu y C ’O

00 •H 'w' 4J h fH n y ^ O ^ •J y c y o y

pL, ss W w O w

1 67 0.214 3.636 .065 .766 .0986 .7782

2 72 0.231 12.727 .227 .807 .3523 2.9400

3 77 0.216 21.818 .389 .847 .5378 3.7127

4 82 0.161 30.909 .551 .888 .5422 4.9764

5 87 0.104 40.000 .713 .928 .4333 4.1600

6 92 0.052 49.091 .874 .969 .2548 2.5527

7 97 0.018 58.182 1 1 .0977 1.0105

8 102 0.004 67.273 1 1 .0217 .2246

2.3384 21.3551 Totals

21.3551

CSPF - 2.68

(2.3384 K3.413)

(800)(60)(.04)

Seasonal Operating Cost = " —

(2.68)(3.413)

Region (1, II, III, IV, V, VI). ^

Cooling Load Hours. 800 (hrs)

Regional Outdoor Temperature. 9^ (°F)

/ / Minimum / / Maximum

Design Cooling Requirement. ^ (kBCu/h)

$210

A-8
Table A3 Sample Worksheet Used to Evaluate the HSPF and Seasonal Cost of Operation

column (a) (b) (c) (d) (e) (f) (g) (h). ( 1 )

u

0) *io

:z

0) H

>

C u

0) (0

CO u

0) 0) u a

CL 6

<D 01 PS H

O

«0 ,

(0o ^

M ^ <4-1

/-V M a cn 3 rH w ^

CO

3

4J s

U — CO f—

3 (U 0) s

** /-N U iH 4J « Li X CO W d CO cd CO Cd 3 Of PJ U 0)<CD' o

CL c ^ c o 1 h4 II i

0) c /—

3 a (d TJ 60

P4 0) 9 4J >- C '3

/-N X 60 w rH CO •H w

H CL 4J Nw' H cd 0) ^ CL CO u Cd /«-N 1-3 h3 0) C o 3 <D (U o

P3 Plh 5C W CO PS 5C w

1 62 0.132 4.235 .081 .853 .0655 .5590

2 57 0.111 11.293 .215 .874 .1434 1.2536

3 52 0.103 18.352 .350 .896 .2110 1.8902

4 47 0.093 25.410 .484 .917 .2576 2.3631

5 42 0.100 32.468 .618 .939 .3458 3.2468

6 37 0.109 39.527 .753 .960 .4486 4.3084

7 32 0.126 46.585 .887 .982 .5977 5.8697

8 27 0.087 53.643 1 1 .4568 .0291 4.6670

9 22 0.055 60.702 1 1 .2888 .1322 3.3386

10 17 0.036 57.760 1 1 .1890 .1610 2.4394

11 12 0.026 74.818 1 1 .1365 .1700 1.9453

12 7 0.013 81.877 1 1 .0682 .1119 1.0644

13 2 0.006 88.935 1 1 .0315 .0641 .5336

14 -3 0.002 95.993 1 1 .0105 .0255 .1920

15 -8 0.001 103.052 1 1 .0052 .0148 .1031

3.2564 .7086 33.7774

Region (I, II, III, IV, V, VI) -

Cooling Load Hours - 2250 (hrs)

Regional Outdoor Design Temperature ^ (®F)

/ / Minimum /X/ Maximum /~7 Intermediate

Design Heating Requirement - 110 (kBtu/h)

33.7774

HSPF 2.50

(3.413K3.2561 + 7086)

(2250)(.77)(110)(.04)

Seasonal Operating Cost

(2.50)(3.413)

$210

A-9
Table AA . Example of Information Which Would Assist A Consumer In Purchasing A Heat Pump

Region

Design

Cooling

Requirement

(KBTU/hr)

Operating Cost in Cooling Season

CSPF .02 .04 .06 .08 .1

Design

Heating

Requirement

(KBTU/hr) HSPF

Operating Cost in Heating Season

Cost of Fuel ($/Kwh)

.02 .04 .06 .8 .1

I 750 2400 CLH

50

25

30

3540

50

60

70

II 1250 HLH

1800 CLH

50

3540

5060

70

III 1750 HLH

1200 CLH

3540

50

40

50

60

7080

25 2.45 50 95 145 190 240 , 50 2.65 190 385 575 765 960

IV 30 2.48 55 115 170 225 285 60 2.69 225 455 675 905 1130

2250 HLH 35 2.51 65 130 195 260 325 70 2.71 260 525 785 1050 1310 800 CLH 40 2.55 75 145 220 295 370 80 2.70 300 600 900 1200 1500

50 2.61 90 180 270 360 450 90 2.66 345 685 1030 1375 1715

60 2.67 105 210 315 420 525 100 2.58 390 790 1180 1575 1970

110 2.50 445 895 1340 1785 2235

15 70 V* 20 80

2750 HLH 25 090

400 CLH 30 100

35 110

40 130

50 150

60 170

VI 30 2750 HLH 50 35 200 CLH 60 40

5060

* Manufacturers should be given the option of stating that "This heat pump is not recommended for use in this region" or some equivalent phrase.

A-10
NBS-114A (REV. 2 -80 ) U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

1. PUBLICATION OR

REPORT NO.

2. Performing Organ. Report No. 3. Publication Date

SHEET (See instructions) NBSIR 81-2434 November 1982

4. TITLE AND SUBTITLE

Method of Testing, Rating and Estimating the Seasonal Performance of Ground WaterSource Heat Pumps

5. AUTHOR(S)

William J. Mulroy

6. PERFORMING ORGANIZATION (If joint or other than NBS, see instructions) 7. Contract/Grant No. NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

8. Type of Report & Period Covered

9. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street. City, State, ZIP)

Department of Energy

20 Massachusetts Avenue, NW

Washington, D.C. 20585

10. SUPPLEMENTARY NOTES

1 1 Document describes a computer program; SF-185, FIPS Software Summary, is attached

11. ABSTRACT {A 200-word or less factual summary of most significant information. If document includes a significant

bibliography or literature survey, mention it here)

The National Bureau of Standards has made a study of the part-load and seasonal

performance of residential ground water source heat pumps operating in both heating

and cooling modes. This document outlines methods for testing and rating these

units which account for the variation in performance due to part-load operation

and change in source water temperature. A calculation procedure is presented

which can be used to estimate the seasonal performance and seasonal cost of operation of residential ground water source heat pumps.

12. KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolons)

Central air conditioners; heat pumps; rating procedure; seasonal cost of

operation; test method

12. AVAILABILITY 14. NO. OF

PRINTED PAGES

[2Q Unlimited

54

1 1 For Official Distribution. Do Not Release to NTIS

r 1 Order From Superintendent of Documents, U.S. Government Printing Office, Washington, D.C.

15. Price 20402.

Order From National Technical Information Service (NTIS), Springfield, VA. 22161 $9.00

USCOMM-DC 8043-P80
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