Heat pump water heaters — Testing and rating for performance — Part 2: Heat pump water heaters for space heating

This document specifies test conditions and test procedures for determining the performance characteristics of air source heat pump water heaters for space heating with electrically driven compressors with or without supplementary heater. The purpose of this document is to rate the performance of the heat pump water heaters for space heating with no operation of any supplementary heater. In the case of heat pump water heaters for space heating consisting of several parts with refrigerant or water connections, this document applies only to those designed and supplied as a complete package. NOTE Testing procedures for simultaneous operation for hot water supply and space heating are not treated in this document. Simultaneous means that hot water supply and space heating generation occur at the same time and can interact.

Chauffe-eau à pompe à chaleur — Essais et classification des performances — Partie 2: Chauffe-eau à pompe à chaleur pour le chauffage des locaux

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Published
Publication Date
18-Jun-2019
Current Stage
9092 - International Standard to be revised
Start Date
06-Sep-2021
Completion Date
06-Sep-2021
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INTERNATIONAL ISO
STANDARD 19967-2
First edition
2019-06
Heat pump water heaters — Testing
and rating for performance —
Part 2:
Heat pump water heaters for space
heating
Chauffe-eau à pompe à chaleur — Essais et classification des
performances —
Partie 2: Chauffe-eau à pompe à chaleur pour le chauffage des locaux
Reference number
ISO 19967-2:2019(E)
ISO 2019
---------------------- Page: 1 ----------------------
ISO 19967-2:2019(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2019

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
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Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 19967-2:2019(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Symbols and abbreviated terms ........................................................................................................................................................... 2

5 Installation requirements........................................................................................................................................................................... 2

5.1 Test apparatus and uncertainties of measurement ................................................................................................. 2

5.2 Test room for the airside and remote condenser ...................................................................................................... 4

5.3 Installation and connection of the heat pump ............................................................................................................. 4

5.4 Installation of heat pumps consisting of several parts ......................................................................................... 4

6 Setting and test conditions......................................................................................................................................................................... 4

6.1 General ........................................................................................................................................................................................................... 4

6.2 Settings for non-ducted units ..................................................................................................................................................... 4

6.3 Setting the external static pressure difference for ducted units .................................................................. 5

6.4 Setting of units with integral pumps .................................................................................................................................... 5

6.5 Test conditions ........................................................................................................................................................................................ 6

7 Space heating test ................................................................................................................................................................................................ 7

7.1 Heating capacity test .......................................................................................................................................................................... 7

7.2 Heating capacity correction ......................................................................................................................................................... 8

7.2.1 General...................................................................................................................................................................................... 8

7.2.2 Capacity correction of fans for units without duct connection ............................................... 8

7.2.3 Capacity correction due to indoor fan for ducted units ................................................................. 8

7.2.4 Capacity correction due to indoor liquid pump .................................................................................... 8

7.2.5 Effective power input ................................................................................................................................................10

7.3 Test procedure ......................................................................................................................................................................................11

7.3.1 General...................................................................................................................................................................................11

7.3.2 Preconditioning period ...........................................................................................................................................11

7.3.3 Equilibrium period .................. ......................................................................................................................... ...........12

7.3.4 Data collection period ..............................................................................................................................................12

7.4 Heating capacity calculation ....................................................................................................................................................12

7.4.1 Steady state capacity test ......................................................................................................................................12

7.4.2 Transient capacity test .............................................................................................................................................12

7.5 Effective power input calculation ........................................................................................................................................12

7.5.1 Steady state test .............................................................................................................................................................12

7.5.2 Transient with defrost cycle ...............................................................................................................................12

7.5.3 Transient without defrost cycle .......................................................................................................................12

8 Test results and test report ....................................................................................................................................................................13

8.1 Data to be recorded ..........................................................................................................................................................................13

8.2 Test report ................................................................................................................................................................................................13

9 Marking .......................................................................................................................................................................................................................14

Annex A (informative) Maximum and minimum operation ......................................................................................................15

Annex B (normative) Heating capacity test procedures given in 7.2 and 7.3 .........................................................17

Annex C (normative) Determination of the liquid pump efficiency..................................................................................21

Bibliography .............................................................................................................................................................................................................................25

© ISO 2019 – All rights reserved iii
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ISO 19967-2:2019(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso

.org/iso/foreword .html.

This document was prepared by Technical Committee ISO/TC 86, Refrigeration and air-conditioning,

Subcommittee SC 6, Testing and rating of air-conditioners and heat pumps.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/members .html.
iv © ISO 2019 – All rights reserved
---------------------- Page: 4 ----------------------
INTERNATIONAL STANDARD ISO 19967-2:2019(E)
Heat pump water heaters — Testing and rating for
performance —
Part 2:
Heat pump water heaters for space heating
1 Scope

This document specifies test conditions and test procedures for determining the performance

characteristics of air source heat pump water heaters for space heating with electrically driven

compressors with or without supplementary heater. The purpose of this document is to rate the

performance of the heat pump water heaters for space heating with no operation of any supplementary

heater. In the case of heat pump water heaters for space heating consisting of several parts with

refrigerant or water connections, this document applies only to those designed and supplied as a

complete package.

NOTE Testing procedures for simultaneous operation for hot water supply and space heating are not treated

in this document. Simultaneous means that hot water supply and space heating generation occur at the same

time and can interact.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
heat pump water heater for space heating
heat pump

air source heat pump water heater with electrically driven compressors with or without supplementary

heater for space heating purposes
3.2
heating capacity
heat given off by the unit to the heat transfer medium per unit of time
Note 1 to entry: Heating capacity is expressed in watts.

Note 2 to entry: If heat is removed by the indoor heat exchanger for defrosting, it is taken into account.

3.3
standard heating capacity

rated heating capacity under standard rating conditions as defined in Tables 5, 6 and 7

© ISO 2019 – All rights reserved 1
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ISO 19967-2:2019(E)
3.4
effective power input

average electrical power input of the unit within the defined interval of time obtained from:

— power input for operation of the compressor and any power input for defrosting;

— power input for all control and safety devices of the unit;

— proportional power input of the conveying devices (e.g. fans, pumps) for ensuring the transport of

the heat transfer media inside the unit
Note 1 to entry: Effective power input is expressed in watts.
3.5
outdoor air
air from the outdoor environment
3.6
operating range
working range for the heat pump as specified by the manufacturer
3.7
outdoor heat exchanger

heat exchanger which is designed to remove heat from the outdoor ambient environment, or any other

available heat source, or to transfer heat to it
4 Symbols and abbreviated terms
Symbol Definition Units
C Specific heat capacity of water kJ/(kg*K)
C A scaling factor equal to 0,49 —
EEI The Energy Efficiency Index equal to 0,23 —
IE The motor efficiency level —
P Heating capacity W
P The hydraulic power of the pump W
hyd
q Volume flow rate m /s
t Time s
ρ Density of the hot water depending on the temperature at the flow meter kg/m
Δp The measured available external static pressure difference Pa
Δp The measured internal static pressure difference Pa
Δt Difference between inlet and outlet temperatures K
η 0,3 by convention —
5 Installation requirements
5.1 Test apparatus and uncertainties of measurement

The test apparatus shall be designed in such a way that all requirements for adjustment of set values,

stability criteria and uncertainties of measurement according to this document are fulfilled.

Water systems or other heat transfer liquid systems shall be sufficiently free of entrained gas as to

ensure that the measured results are not significantly influenced.
2 © ISO 2019 – All rights reserved
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ISO 19967-2:2019(E)

The inlet and outlet water temperatures of the heat pump are measured in the centre of the flow and

as close as possible to the unit. The response time of the temperature sensor and the sampling interval

shall be chosen to maintain the uncertainties in Table 1.

Ducted air systems shall be sufficiently airtight to ensure that the measured results are not significantly

influenced by exchange of air with the surroundings.

When performing measurements, set the highest room temperature on the unit/system control device.

If in the instructions, the manufacturer indicates a value for the temperature set on the control device

for a given rating condition, then this value shall be used.

Temperature and pressure measuring points shall be arranged in order to obtain mean significant values.

For free air intake temperature measurements, it is required either:

— to have at least one sensor per square meter, with not less than four measuring points and by

restricting to 20 the number of sensors equally distributed on the free air surface; or

— to use a sampling device. It shall be completed by four sensors for checking uniformity if the surface

area is greater than 1 m .

Air temperature sensors shall be placed at a maximum distance of 0,25 m from the free air surface.

For units consisting of a heat pump and a storage tank as a factory made unit, water inlet and outlet

temperature measurements shall be taken at the inlet and outlet of this unit.

For water and brine, the density and specific heat in Formulae (1), (2) and (3) shall be determined in the

temperature conditions measured near the volume flow measuring device.

For inverter type control units, the setting of the frequency shall be done for each rating condition.

The manufacturer shall provide in the documentation information instructions on how to obtain the

necessary data to set the required frequencies. If skilled personnel with knowledge of control software

is required for the start of the system, the manufacturer or the nominated agent should be in attendance

when the system is being installed and prepared for tests.

The uncertainties of measurement shall not exceed the values specified in Table 1. Additionally, the

heat capacity measured on the liquid side shall be determined within a maximum uncertainty of 5 %

independently of the individual uncertainties of measurements including the uncertainties on the

properties of the fluid.
Table 1 — Uncertainties of measurement
Measured quantity Unit Uncertainty
Liquid
Temperature °C ±0,15 K
Temperature difference K ±0,15 K
Volume flow l/min ±1 %
±1 kPa (≤20 kPa)
Static pressure difference kPa
±5 % (>20 kPa)
Concentration (for brine) % 2 %
Air
Dry bulb temperature °C ±0,2 K
Wet bulb temperature °C ±0,4 K
Volume flow m /h ±5 %
±5 Pa (∆P ≤ 100 Pa)
Static pressure difference Pa
±5 % (∆P ≥ 100 Pa)
© ISO 2019 – All rights reserved 3
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ISO 19967-2:2019(E)
Table 1 (continued)
Measured quantity Unit Uncertainty
Electrical quantities
Electric power W ±1 %
Electrical energy kWh ±1 %
Voltage V ±0,5 %
current A ±0,5 %
5.2 Test room for the airside and remote condenser

The size of the test room shall be selected to avoid any resistance to air flow at the air inlet and air

outlet orifices of the test object. The air flow through the room shall not be capable of initiating any

short circuit between the two orifices, and therefore the velocity of air flow at these two locations shall

not exceed 1,5 m/s when the test object is switched off.

Unless otherwise stated by the manufacturer, the air inlet and air outlet orifices shall not be less than

1 m from the surfaces of the test room.

Any direct heat radiation (e.g. solar radiation) onto heating units in the test room onto the heat pump or

onto the temperature measuring points shall be avoided.
5.3 Installation and connection of the heat pump

The heat pump shall be installed and connected for the test as recommended by the manufacturer in the

installation and operation manual. If a back-up heater is provided in option or not, it shall be switched

off or disconnected to be excluded from the testing. Temperature and pressure measuring points shall

be arranged in order to obtain representative mean values.
5.4 Installation of heat pumps consisting of several parts

In the case of heat pumps consisting of several refrigeration parts (split heat pumps), the following

installation conditions shall be complied with for the tests:

a) each refrigerant line shall be installed in accordance with the manufacturer's instructions; the

length of each line shall be between 5 m and 7,5 m;

b) the lines shall be installed so that the difference in elevation does not exceed 2,5 m;

c) thermal insulation shall be applied to the lines in accordance with the manufacturer's instructions;

d) unless constrained by the design, at least half of the interconnecting lines shall be exposed to the

outdoor conditions with the rest of the lines exposed to the indoor conditions.
6 Setting and test conditions
6.1 General

Set points for internal control equipment of the unit, i.e. thermostats, pressure switches or mixing

valves, shall be set to the values as stated in the installation and operating instructions.

If several set points or a range are stated, the manufacturer shall indicate the one to be used for the tests.

6.2 Settings for non-ducted units

For non-ducted units, the adjustable settings, i.e. louvers and fan speed, shall be set according to the

installations and operating instructions.
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ISO 19967-2:2019(E)

Without information from the manufacturer, louvers and fan speed shall be set for maximum air flow rate.

6.3 Setting the external static pressure difference for ducted units

The volume flow and the pressure difference shall be related to standard air and with dry heat

exchanger. If the air flow rate is given by the manufacturer with no atmospheric pressure, temperature

and humidity conditions, it shall be considered as given for standard air conditions.

The air flow rate as stated in the installation and operating instructions shall be converted into

standard air conditions. The air flow rate setting shall be made when the fan only is operating.

The rated air flow rate as stated in the installation and operating instructions shall be set and the

resulting external static pressure (ESP) measured.

If the ESP is lower than 30 Pa, the air flow rate is decreased to reach this minimum value. The apparatus

used for setting the ESP shall be maintained in the same position during all the tests.

If the installation and operating instructions state that the maximum allowable duct length is for inlet

and outlet together less than 2 m, then the unit shall be tested with the duct length and the ESP is

considered to be 0.
6.4 Setting of units with integral pumps

For units with integral water or brine pumps, the external static pressure shall be set at the same time

as the temperature difference.

When the liquid pump has one or several fixed speeds, the speed of the pump shall be set in order to

provide the minimum external static pressure.

In case of variable speed liquid pump, the manufacturer shall provide information to set the pump in

order to reach a maximal external static pressure of 10 kPa.

Deviations from set values shall not exceed values indicated in Table 2. Variations from specified

conditions shall not exceed values indicated in Table 3.
Table 2 — Permissible deviations from set values
Permissible deviation of the Permissible deviations of indi-
Measured quantity arithmetic mean values from vidual measured values from set
set values values
Liquid
— inlet temperature ±0,2 K ±0,5 K
— outlet temperature ±0,3 K ±0,6 K
— volume flow ±1 % ±2,5 %
— static pressure difference — ±10 %
Air
— inlet temperature
— dry bulb ±0,3 K ±1 K
— wet bulb ±0,4 K ±1 K
— volume flow ±5 % ±10 %
— static pressure difference — ±10 %
Voltage ±4 % ±4 %
Frosting period excluded.
© ISO 2019 – All rights reserved 5
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ISO 19967-2:2019(E)

Table 3 — Variations allowed for the test conditions when the heat pump is running

Variations of arithmetical mean
Variation of individual readings
Readings values from specified test condi-
from specified test conditions
tions
Interval Interval Interval Interval
a b a b
H D H D
Air
— dry-bulb temperature ±0,6 K ±1,5 K ±1,0 K ±5,0 K
— wet-bulb temperature ±0,4 K ±1,0 K ±0,6 K —
Liquid
— inlet temperature ±0,2 K — ±0,5 K -5 K
— outlet temperature ±0,5 K — ±1 K +2 K

Interval H applies when the heat pump is in the heating mode, except for the first 10 min after termination of a defrost

cycle, and the first 10 min after a restart of the heat pump.

Interval D applies during a defrost cycle and during the first 10 min after the termination of a defrost cycle when the

heat pump is operating in the heating mode.
c 2

For units with outdoor heat exchanger surfaces greater than 5 m , the deviation on the air inlet dry bulb temperature

is doubled.
6.5 Test conditions

The space heating tests shall be carried out under the environmental conditions specified in Table 4

depending on the location of the unit. For all units, electrical power voltage and frequency shall be

given by the manufacturer.

For the rating tests, the appropriate test conditions shall be applied in accordance with Tables 5, 6 and 7.

The airflow rate shall be set to nominal, as indicated by the manufacturer. When only a range is given,

tests are to be carried out at the maximum value
Table 4 — Environmental conditions
Type Measured quantities Environmental temperature
Air-to-water units installed indoors Dry bulb temperature 15 °C to 30 °C

Air-to-water units installed outdoors Dry bulb temperature Air inlet temperatures

Wet bulb temperature (see Tables 5 6 and 7)
Table 5 — Test conditions for space heating (Low temperature)
Outdoor heat exchanger Indoor heat exchanger
Low temperature applications
Inlet dry bulb Inlet wet bulb Inlet tempera- Outlet
temperature temperature ture temperature
°C °C °C °C
Standard
7 6 30 35
rating conditions
Application 2 1 35
Rating conditions
−7 −8 35
−15 — 35
12 11 35

The test is performed at the flow rate obtained during the test at the standard rating conditions.

6 © ISO 2019 – All rights reserved
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ISO 19967-2:2019(E)
Table 6 — Test conditions for space heating (Medium temperature)
Indoor heat exchanger
Outdoor heat exchanger
Medium temperature applications
Inlet dry bulb Inlet wet bulb Inlet Outlet
temperature temperature temperature temperature
°C °C °C °C
Standard
7 6 40 45
rating conditions
Application 2 1 45
Rating conditions
−7 −8 45
−15 — 45
12 11 45

The test is performed at the flow rate obtained during the test at the standard rating conditions.

Table 7 — Test conditions for space heating (High temperature)
Indoor heat exchanger
Outdoor heat exchanger
High temperature applications
Inlet dry bulb Inlet wet bulb Inlet Outlet
temperature temperature temperature temperature
°C °C °C °C
Standard
7 6 47 55
rating conditions
Application 2 1 55
Rating conditions
−7 −8 55
−15 — 55
12 11 55

The test is performed at the flow rate obtained during the test at the standard rating conditions.

7 Space heating test
7.1 Heating capacity test

The heating capacity of heat pumps shall be determined in accordance with the direct method at the

water or brine heat exchanger at test conditions of Tables 5, 6 and 7, by determination of the volume

flow of the heat transfer medium, and the inlet and outlet temperatures, taking into consideration the

specific heat capacity and density of the heat transfer medium.

For steady state operation, the heating capacity shall be determined using the following formula:

Pq=×ρ××CtΔ (1)
where
© ISO 2019 – All rights reserved 7
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ISO 19967-2:2019(E)
P is the heating capacity in watts;
q is the volume flow rate, expressed in cubic meters per second;

ρ is the density, measured at the flow meter location, expressed in kilograms per cubic meter;

C is the specific heat, measured at the flow meter location, at constant pressure, expressed in

joules per kilogram and kelvin;

Δt is the difference between inlet and outlet temperatures, expressed in kelvin;

NOTE 1 The mass flow rate can be determined directly instead of the term (q × ρ).

NOTE 2 The enthalpy change ΔH can be directly measured instead of the item (C × Δt).

7.2 Heating capacity correction
7.2.1 General

The capacity shall include the correction due to the heat output of indoor and/or outdoor fans and/or

pumps, integrated into the unit or not as follows.
7.2.2 Capacity correction of fans for units without duct connection

In the case of units which are not designed for duct connection, i.e. which do not permit any external

pressure difference, and which are equipped with an integral fan, no capacity correction due to heat

provide by the fan shall apply.
7.2.3 Capacity correction due to indoor fan for ducted units
7.2.3.1 Units with integrated indoor fan

If the fan at the indoor heat exchanger is an integral part of the unit, the power input correction of the

fan, as calculated with Formula (6) (see 7.2.5.3.1) shall be:
— subtracted from the measured heating capacity.
7.2.3.2 Units with non-integrated indoor fan

If the fan at the indoor heat exchanger is not an integral part of the unit, the power input correction as

calculated with Formula (7) (see 7.2.5.3.2) shall be:
— added to the measured heating capacity.
7.2.4 Capacity correction due to indoor liquid pump
7.2.4.1 Units with integrated liquid pump

If the liquid pump is an integrated part of the unit, the capacity correction as defined in 7.2.4.3 or 7.2.4.4

shall be:
— subtracted from the measured heating capacity.
7.2.4.2 Units with non-integrated liquid pump

If the liquid pump is not an integral part of the unit, the capacity correction as defi

...

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