ISO 19967-1:2019

Heat pump water heaters — Testing and rating for performance — Part 1: Heat pump water heater for hot water supply

This document specifies test conditions and test procedures for determining the performance characteristics of air source heat pump water heaters for hot water supply with electrically driven compressors with or without supplementary electric heater and connected to or including only one hot water storage tank. Hot water storage tanks that are connected in series or parallel and behave hydronically as one single tank are considered as one hot water storage tank. In the case of heat pump water heaters consisting of several parts with refrigerant or water connections, this document applies only to those designed and supplied as a complete package. NOTE This document is not applicable to testing procedures for simultaneous operation for hot water supply and space heating. "Simultaneous" means that hot water supply and space heating generation occur at the same time and may interact.

Chauffe-eau à pompe à chaleur — Essais et classification des performances — Partie 1: Chauffe-eau à pompe à chaleur pour l'alimentation en eau chaude

General Information

• Status: Published
• Publication Date: 18-Mar-2019
• ICS: 27.080 - Heat pumps
• Technical Committee: ISO/TC 86/SC 6 - Testing and rating of air-conditioners and heat pumps
• Drafting Committee: ISO/TC 86/SC 6/WG 12 - Heat pump water heaters
• Current Stage: 6060 - International Standard published
• Start Date: 19-Mar-2019
• Completion Date: 19-Mar-2019

Standards Content (sample)

INTERNATIONAL ISO
STANDARD 19967-1
First edition
2019-03
Heat pump water heaters — Testing
and rating for performance —
Part 1:
Heat pump water heater for hot
water supply
Chauffe-eau à pompe à chaleur — Essais et classification des
performances —
Partie 1: Chauffe-eau à pompe à chaleur pour l'alimentation en
eau chaude
Reference number
ISO 19967-1:2019(E)
ISO 2019
---------------------- Page: 1 ----------------------
ISO 19967-1:2019(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

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Published in Switzerland
ii © ISO 2019 – All rights reserved
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ISO 19967-1:2019(E)
Contents Page

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

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

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

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

4 Symbols and abbreviated terms ........................................................................................................................................................... 3

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

5.1 Test apparatus and uncertainties of measurement ................................................................................................. 5

5.2 Test room for the outdoor heat exchanger of air source heat pump water heaters ................... 5

5.3 Installation and connection of the heat pump water heaters......................................................................... 6

5.4 Installation of heat pump water heater consisting of several parts ......................................................... 6

6 Settings and test conditions ...................................................................................................................................................................... 6

6.1 General ........................................................................................................................................................................................................... 6

6.2 Settings for non-ducted air source units .......................................................................................................................... 6

6.3 Setting the external static pressure difference for ducted air source units ....................................... 7

6.4 Test conditions ........................................................................................................................................................................................ 7

6.4.1 General test conditions ............................................................................................................................................... 7

6.4.2 Additional test conditions ........................................................................................................................................ 7

7 Performance test and determination of the energy consumption ................................................................... 9

7.1 General ........................................................................................................................................................................................................... 9

7.2 Basic principles....................................................................................................................................................................................... 9

7.3 Off-peak products ..............................................................................................................................................................................10

7.4 Power input corrections ..............................................................................................................................................................11

7.4.1 Power input of fans for heat pump water heater with duct connection .......................11

7.5 Stabilization [stage A] ....................................................................................................................................................................12

7.6 Filling and storage [stage B] .....................................................................................................................................................12

7.7 Filling and heating up period [stage C] ...........................................................................................................................12

7.8 Standby power input [stage D] ..............................................................................................................................................13

7.9 Water draw-offs and COP calculation [stage E] .......................................................................................................13

7.9.1 Determination of the useful energy content .........................................................................................13

7.9.2 Determination of the energy consumption ............................................................................................15

7.9.3 Coefficient of performance (COP ) ..........................................................................................................16

7.10 Reference hot water temperature and volume of mixed water at 40 °C [stage F] .....................16

7.11 Units with smart control ......... .....................................................................................................................................................17

7.12 Temperature operating range .................................................................................................................................................17

8 Test results and test report ....................................................................................................................................................................17

8.1 Data to be recorded ..........................................................................................................................................................................17

8.2 Test report ................................................................................................................................................................................................18

8.2.1 General information ...................................................................................................................................................18

8.2.2 Main results .......................................................................................................................................................................19

9 Marking .......................................................................................................................................................................................................................19

Annex A (normative) Load profiles .....................................................................................................................................................................20

Annex B (informative) Determination of the smart control factor SCF .........................................................................22

Annex C (informative) Temperature operating range .....................................................................................................................28

Bibliography .............................................................................................................................................................................................................................30

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ISO 19967-1:2019(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.
A list of all parts in the ISO 19967 series can be found on the ISO website.

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
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INTERNATIONAL STANDARD ISO 19967-1:2019(E)
Heat pump water heaters — Testing and rating for
performance —
Part 1:
Heat pump water heater for hot water supply
1 Scope

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

characteristics of air source heat pump water heaters for hot water supply with electrically driven

compressors with or without supplementary electric heater and connected to or including only one

hot water storage tank. Hot water storage tanks that are connected in series or parallel and behave

hydronically as one single tank are considered as one hot water storage tank. In the case of heat pump

water heaters consisting of several parts with refrigerant or water connections, this document applies

only to those designed and supplied as a complete package.

NOTE This document is not applicable to testing procedures for simultaneous operation for hot water supply

and space heating. “Simultaneous” means that hot water supply and space heating generation occur at the same

time and may 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.e lectropedia. org/
3.1
heat pump water heater for hot water supply

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

supplementary electrical heater and connected to or including a hot water storage tank for hot water

supply for human use
3.2
hot water supply
water heated for human use or household or similar purposes
3.3
storage volume
measured volume of hot water that can be contained in the storage tank
3.4
non heated space air

heat source for a heat pump which absorbs heat by an air heat exchanger in direct contact with the air

inside a space in a building which is not heated
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ISO 19967-1:2019(E)
3.5
coefficient of performance for hot water supply
COP

coefficient of performance which is determined by the use of reference load profiles and which includes

the heat losses of the storage tank
3.6
reference hot water temperature

temperature determined as the mean temperature value of the average temperatures during one single

draw-off which ends when the hot water temperature is below 40 °C
3.7
volume of mixed water at 40 °C

volume of water at 40 °C, which has the same heat content (enthalpy as the hot water which is delivered

above 40 °C at the output of the heat pump water heater
3.8
off-peak product

heat pump water heater that is energised for a maximum period of eight consecutive hours between

22:00 and 07:00 of the 24-h tapping pattern
3.9
load profile
given sequence of water draw-offs
Note 1 to entry: See Annex A.
3.10
water draw-off

given combination of useful water flow rate, useful water temperature, useful energy content and

target temperature
3.11
useful water flow rate
f(t)
minimum flow rate for the draw-off of the load profile
3.12
useful water temperature
minimum hot water temperature for the draw-off of the load profile
3.13
useful energy content
tap

energy content of hot water provided at a temperature equal to, or above, the useful water temperature,

and at water flow rates equal to, or above, the useful water flow rate
3.14
target temperature

minimum water temperature to be achieved during water draw-off calculated as the mean value over

the water draw off
3.15
reference energy of the load profile
ref
sum of the useful energy content of water draw-offs in a particular load profile
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ISO 19967-1:2019(E)
3.16
smart control

device that automatically adapts the water heating process to individual usage conditions with the aim

of reducing energy consumption
3.17
smart control factor
SCF
water heating energy efficiency gain due to smart control
3.18
standby power input

total power input of the unit during the standby test, including the power input of the unit to overcome

heat losses of the tank and the power input of any auxiliary device
3.19
coefficient of performance of smart control products
COP
smart
coefficient of performance of unit that can take benefit from a smart control
3.20
nominal volume

volume of water that is assigned to the storage tank by the manufacturer and that is marked on the tank

3.21
operating range
working range for the heat pump water heater as specified by the manufacturer
4 Symbols and abbreviated terms
Symbol Description Units
SCF smart control factor —
COP coefficient of performance for a given reference load profile —
COP coefficient of performance of smart control products —
smart
C specific heat capacity of water kJ/(kg·K)
Δp measured external static pressure difference Pa
Δp measured internal static pressure difference Pa

f minimum flow rate for which hot water is contributing to the reference energy l/min

f maximum flow rate of considered load profile l/min
max
f (t) flow rate of hot water during draw-off l/min
max
f(t) useful water flow rate l/min
i index for the draw-off —

m difference of the two weights (filled / empty) of the hot water storage tank kg

act
η efficiency of the fan is 0.3 -
n number of draw-offs during the load profile —
tap
P standby power input kW
P measured average power consumption for off-peak products kW

Q calculated heat energy produced by electrical resistance heater during the whole load profile kWh

EL-LP

Calculated heat energy produced by electrical resistance heater to reach the required

Q kWh
EL-tap
tapping temperature
Q useful energy during one single draw-off kWh
HP-tap
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ISO 19967-1:2019(E)
Symbol Description Units
Q total useful energy content during the whole load profile kWh
total useful energy consumption during the smart period of the smart cycle
smart
kWh
elec
total useful energy content during the smart period of the smart cycle
smart
kWh
Total electricity consumption during the reference period of the smart cycle
ref
kWh
elec
total useful energy content during the reference period of the smart cycle
ref
kWh
Total electricity consumption of the WHL control cycle
WHL,C
kWh
elec
Q reference energy of the considered load profile kWh
ref

energy content of hot water provided at a temperature equal to, or above, the useful

Q kWh
tap

water temperature, and at water flow rates equal to, or above, the useful water flow rate

ρ(T) density of water at temperature T kg/m
t test phase duration s
t duration of the last on-off-cycle of the heat pump water heater s
t heating up time s
t time from starting the draw-off until θ is less than 40 °C s
40 WH
t duration of a draw-off of useful water s
tap
t load profile time / duration h
TTC
T dry bulb temperature °C

T useful water temperature at which hot water starts contributing to the reference energy °C

T target water temperature to be achieved during water draw-off °C
T Wet bulb temperature °C
θ incoming cold water temperature °C
θ (t) incoming cold water temperature during draw-off °C
θ outgoing hot water temperature °C
θ (t) hot water temperature during draw-off °C
θ' reference hot water temperature °C
V nominal air volume flow rate m /s
air
V measured liquid volume flow rate m /s
Fluid
V measured volume of a hot water storage tank l
V mixed volume of mixed water at 40 °C l

V volume of water that is assigned to the storage tank by the manufacturer and marked on it l

W total electricity consumption during the test duration t kWh
eh-HP h
W measured electricity consumption during the test duration t kWh
eh-M h
W correction due to electricity consumption of fan/liquid pump kWh
EL-Corr
W total electrical energy consumption during the whole load profile kWh
EL-LP
W total measured electrical energy input kWh
EL-M-LP
W calculated energy consumption for off-peak products kWh
EL-OFF
W total energy input during the last on-off-cycle kWh
es-HP
W measured energy consumption during the last on-off cycle kWh
es-M
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ISO 19967-1:2019(E)
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 can be 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.

The inlet and outlet temperatures of the hot water supply are measured in the centre of the flow and

as close as possible to the appliance. 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.

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 obtaining the necessary

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

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.

Table 1 — Uncertainties of measurement
Measured quantity Unit Uncertainty
Hot water supply
Temperature °C 0,15 K
Temperature difference K 0,15 K
Volume L 2 %
Volume flow l/min 2 %
Thermal energy kWh 5 %
Air (heat source)
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)
Electrical quantities
For ≥10 W, 1 %
Electric power W
For <10 W, 0.1 W
Electrical energy kWh 1 %
Voltage V 0,5 %
current A 0,5 %
Ambient
Ambient temperature indoors °C 0,5 K

5.2 Test room for the outdoor heat exchanger of air source heat pump water heaters

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

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ISO 19967-1:2019(E)

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; this also applies to any measuring ducts.

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

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

The heat pump water heater shall be installed and connected for the test as recommended by the

manufacturer’s installation and operation manual. The accessories provided by option (for example

heating element) are not included in the test. Temperature and pressure measuring points shall be

arranged in order to obtain representative mean values.
5.4 Installation of heat pump water heater consisting of several parts

In the case of heat pump water heaters consisting of several refrigeration parts (split heat pump water

heater) 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.

For indirect systems where the heat pump water heater is separated from the tank, water or brine

connections to the tank shall be installed in accordance with the manufacturer’s instructions to the

maximum stated length or 5 m whichever is shorter. Piping shall be well insulated and made as short as

possible and with as few bends as possible.
6 Settings and test conditions
6.1 General

Set points for internal control equipment of the unit such as 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.

Thermostat settings and settings for supplementary electrical heaters shall be done according to the

installations and operating instructions and shall remain in the same position for the duration of the

test. If the heat pump water heater is equipped with a mixing valve for the hot water, this valve shall be

set at the manufacturer's recommended setting throughout the test.
6.2 Settings for non-ducted air source units

For non-ducted units, the adjustable settings such as louvers and fan speed shall be set according to the

installation and operating instructions. Without information from the manufacturer, louvers and fan

speed shall be set for maximum air flow rate.
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ISO 19967-1:2019(E)
6.3 Setting the external static pressure difference for ducted air source units

The volume flow and the pressure difference shall be related to standard air and with a 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 Test conditions
6.4.1 General test conditions

The tests shall be carried out at the test conditions specified in Table 3 and Table 4 as appropriate.

Permissible deviations shall not exceed the values specified in Table 2. In addition, the maximal

permissible deviation of thermal energy for the complete load profile shall be less than 5 %.

6.4.2 Additional test conditions

Table 2 — Variations allowed for the test conditions when the heat pump water heater is running

Variations of arithmetical mean values Variation of individual readings from speci-

Readings
from specified test conditions fied test conditions
Interval Interval Interval Interval Interval Interval
a b c a b c
H D S H D S
Air temperature
dry-bulb ±0,6 K ±1,5 K ±1,0 K ±5,0 K ±2,5 K
— wet-bulb ±0,3 K ±1,0 K ±0,6 K —
— volume
±5 % ±10 %
flow
— static
pressure — ±10 %
difference
— ambient
temperature
of the tank
±1 K ±2 K
(if not used as
heat source)

Interval H applies when the heat pump water heater 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 water heater.

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

heat pump water heater is operating in the heating mode.

Interval S applies when the compressor is stopped and during the first 10 min after the hot water thermostat has

started the heat pump water heater again.
d 2

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

is doubled.
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ISO 19967-1:2019(E)
Table 2 (continued)

Variations of arithmetical mean values Variation of individual readings from speci-

Readings
from specified test conditions fied test conditions
Interval Interval Interval Interval Interval Interval
a b c a b c
H D S H D S
hot water supply
— inlet tem-
±1 K ±1 K
perature
— volume ±5 % (≥10 l/min) ±10 % (≥10 l/min)
flow
±0,5 l/min (<10 l/min) ±1,0 l/min (<10 l/min)
Electrical
Voltage ±3 % ±3 %
Frequency ±2 % ±2 %

Interval H applies when the heat pump water heater 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 water heater.

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

heat pump water heater is operating in the heating mode.

Interval S applies when the compressor is stopped and during the first 10 min after the hot water thermostat has

started the heat pump water heater again.
d 2

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

is doubled.
Table 3 — Test conditions applicable to all systems
Measured variable Set value
Power supply voltage Rated voltage
Power suppl
...