Technological solutions used in the design of space heaters and domestic hot water heaters, despite serving similar functional purposes, may differ in their environmental impact. Many solutions available on the market contribute to greater consumption of natural resources than others. At the same time there are designs with high development potential that can improve the energy efficiency of these products. Particular attention should be paid to technologies used in heat pumps.

📄Article: Heat pump testing – methods and standardOpen PDF Download

The aim of EU directives and regulations defining the so-called Ecodesign rules and establishing the framework for energy labelling is to achieve a high level of environmental protection by promoting energy-efficient products, which enables reduction of the negative environmental impact of energy-related products. These regulations define the conditions applicable to these products when placing them on the market or putting them into service. The obligation to provide labelling and to include information on energy efficiency, energy and other resource consumption during use, and to provide additional information, enables customers to make informed choices of more efficient products and allows energy consumption in households and industry to be reduced.

Currently many solutions existing on the market have a significantly greater share in consuming natural resources than others. At the same time there are solutions that have considerable development potential that can be used to improve the energy efficiency of these products.
Technologies used in heat pumps deserve particular attention.
In order to support EU legislation (directives, regulations), harmonised standards are developed that form part of EU law. Application of standards is voluntary; however, products manufactured in accordance with harmonised standards benefit from a presumption of conformity with the relevant essential requirements of directives, regulations or other acts of EU law. By applying harmonised standards the manufacturer can use a simplified process of assessing product conformity with the relevant directive or regulation.
With regard to heat pumps there is a range of harmonised standards on the basis of which equipment performance parameters and fulfilment of safety requirements can be confirmed.

Heat pump testing can be divided into the following categories:

tests concerning energy and operating characteristics;
pressure tightness and strength tests;
acoustic tests;
electrical safety of use tests;
electromagnetic compatibility tests.

ENERGY CHARACTERISTIC TESTS

Heat pump testing – test methods, scope and standards — *Fig. 1. Specimen label for space heaters with a heat pump, excluding low-temperature heat pumps, in seasonal space heating energy efficiency classes from A+++ to D [Source: Regulation (EU) 811/2013)]*

These tests provide information on the energy performance of the equipment in the context of operating costs borne by users. They include determination of energy efficiency indicators based on measurements of heating capacity, refrigerating capacity and effective power input for equipment operating under standardised conditions. The basic coefficients characterising the energy efficiency of heat pumps are: ηs,h, ηs,c, COP, EER, SCOP, SEER.

COP (coefficient of performance for heating) defines the ratio of useful thermal energy obtained to electrical energy input under specific system operating conditions. The value of this coefficient is determined on the basis of laboratory tests under conditions compliant with applicable standards. COP is strongly dependent on these conditions, so it is worth checking whether the manufacturer, presenting data in commercial materials, provides the full product characteristic or is limited to publishing the COP value determined under the most favourable conditions. Tests performed in accordance with the appropriate standard will help users avoid disappointment related to low equipment efficiency and will protect manufacturers against possible claims from customers.

SCOP (seasonal coefficient of performance for heating) is the overall performance coefficient of the equipment for the entire heating season. SCOP defines the ratio of annual heat demand to electricity consumption in the same period.

ηs,h (seasonal space heating energy efficiency) means, expressed in %, the ratio of space heating demand in a specified heating season to the annual energy consumption required to meet that demand.

The base documents for testing heat pumps for space heating with electrically driven compressors are the PN-EN 14511 series of standards. These documents were prepared within the framework of Commission Regulations (EU) Nos 206/2012, 626/2011, 813/2013, 811/2013, 2015/1095 and 2016/2281.

The standard authors distinguish tests under standard rating conditions and application rating conditions. Defined water temperature values under standard rating conditions depending on the temperature application of heat pumps are presented in Table 1.

Table 1. Defined water temperature values under standard rating conditions depending on heat pump temperature application according to PN-EN 14511

Temperature application	Water temperature difference	Outlet water temperature
Low	5K	35°C
Medium	5K	45°C
Intermediate	8K	55°C
High	10K	65°C

For heat pumps with fixed flow rate under application rating conditions, heat carrier temperatures on the heat exchanger inlet side take result values according to the magnitudes of heat carrier flows measured during tests under standard rating conditions.

For units with variable flow rate, tests are performed at a constant water temperature difference for the individual temperature applications.
During heat pump testing a number of parameters defined by the standard are measured, inter alia heat carrier flow rates, heat carrier temperatures at pump inlet and outlet, static pressures, electrical power input. On this basis the heating/refrigerating capacity of the tested equipment, effective power and its energy efficiency coefficients are determined.

Depending on the type of equipment the standard provides for different test methods, such as: determination of heat carrier volume flow and its temperature at water inlet and outlet of the heat exchanger taking into account the specific heat capacity and density of the heat carrier, the calorimetric method and the air enthalpy method.

Detailed test conditions such as temperatures, part-load conditions and calculation methods for determining the seasonal coefficient of performance for heating SCOP, SCOPon and seasonal space heating energy efficiency ηs,h are contained in PN-EN 14825. This standard applies to equipment defined in PN-EN 14511-1 and PN-EN 15879-1. Conditions for determining rating values, test methods and requirements for test apparatus are given in PN-EN 14511-2, PN-EN 14511-3 and PN-EN 15879-1 taking into account additional requirements contained in this standard. An element necessary to determine the heating efficiency coefficient is also measurements performed in thermostat-off mode, standby mode, off mode and crankcase heater mode.

Part-load conditions depend on:

outlet water temperature
flow rate
reference heating season
temperature application

EU Ecodesign regulations for space heaters define average climate conditions as the European reference heating season and low-temperature and medium-temperature applications. Parameters in product fiches should therefore be declared for average climate conditions for low- and medium-temperature applications. Table 2 contains design conditions for space heaters with a heat pump and combination heaters with a heat pump.

Table 2. Design conditions for space heaters with a heat pump and combination heaters with a heat pump, for temperatures defined as dry-bulb air temperature (wet-bulb air temperature is given in parentheses)

Climate conditions	Reference design temperature T_designh	Bivalent temperature T_biv	Operating limit temperature TOL
Average	– 10 (– 11) °C	Maximum + 2 °C	Maximum – 7 °C
Colder	– 22 (– 23) °C	Maximum – 7 °C	Maximum – 15 °C
Warmer	+ 2 (+ 1) °C	Maximum + 7 °C	Maximum + 2 °C

The seasonal space heating energy efficiency class is established on the basis of its seasonal space heating energy efficiency. Classification of air heaters with a heat pump is contained in EU Regulation No 811/2013.

Table 3. Seasonal space heating energy efficiency classes according to EU Regulation No 811/2013

Seasonal space heating energy efficiency class	Seasonal space heating energy efficiency for heaters excluding low-temperature heat pumps and space heaters with a heat pump for low-temperature applications η_s in %	Seasonal space heating energy efficiency for low-temperature heat pumps and space heaters with a heat pump for low-temperature applications η_s in %
A⁺⁺⁺	η_s ≥ 150	η_s ≥ 175
A⁺⁺	125 ≤ η_s < 150	150 ≤ η_s < 175
A⁺	98 ≤ η_s < 125	123 ≤ η_s < 150
A	90 ≤ η_s < 98	115 ≤ η_s < 123
B	82 ≤ η_s < 90	107 ≤ η_s < 115
C	75 ≤ η_s < 82	100 ≤ η_s < 107
D	36 ≤ η_s < 75	61 ≤ η_s < 100
E	34 ≤ η_s < 36	59 ≤ η_s < 61
F	30 ≤ η_s < 34	55 ≤ η_s < 59
G	η_s < 30	η_s < 55

Tests of heat pumps with electrically driven compressors with direct expansion – ground/water (brine) for space heating are performed according to PN-EN 15879-1. The test report should contain at least the following elements for each assessment condition: heating capacity, cooling capacity, effective power input, COP, EER, static pressure drop or external static pressure on the indoor heat exchanger side, superheat, refrigerant charge.

Test procedures for heat pumps with electrically driven compressors for domestic hot water preparation are contained in PN-EN 16147. Tests of a heat pump for domestic hot water using indoor and outdoor air may include: heating-up period, power input in ready-to-operate state, determination of useful energy, measurement of electricity consumption, determination of COP for specified daily water draw-off profiles, determination of seasonal heating efficiency indicator SCOPDHW, determination of seasonal water heating energy efficiency ηwh, determination of reference hot water temperature and maximum DHW volume, operating temperature range, check of safety devices. The seasonal performance coefficient SCOPDHW should be considered equal to COPDHW when it has been determined under conditions defined in the standard in average climate and with the maximum load profile declared by the manufacturer.

TEST REPORT

According to standard requirements, heat pump test results should be presented
in the form of a test protocol (report / statement). Requirements as to the content and form of the protocol are strictly defined in the testing standards, and for accredited tests there are additional requirements resulting from the provisions of PN-EN-ISO/IEC 17025 concerning the quality system. Application of these rules guarantees that the test report is transparent and understandable for the recipient, regardless of in which country and by which laboratory it was prepared.

A test protocol issued in accordance with the provisions of PN-EN 14511-3 should contain at least the following data: date, testing institution, place of test, test method, data of the person supervising the tests, identification of the test object (type, serial number, manufacturer name), type of refrigerant, mass of refrigerant, fluid properties, reference to this European Standard. Additional information contained on the nameplate and any other information relevant to the test should be given. In particular it should be stated whether a new or used product was tested. For tests of used equipment the year of installation and information on cleaning of heat exchanger pipes should be given. Rated capacities, power input, COP, EER, internal or external static pressure should be given together with the rating conditions.

For PN-EN 14825 the report should include general and additional information specified in PN-EN 14511-3 or PN-EN 15879-1, test results and EER or COP calculations at part load; furthermore for hybrid units the test method that was applied should be given. Calculations of seasonal space cooling/heating efficiency ηs,c/ηs,h, SEER/SCOP and SEERon/SCOPnet or seasonal energy efficiency ratio SEPR included in the report should be based on test results. It is not permissible to place in the test report calculations performed on the basis of declared values.

Every report issued by a laboratory accredited in accordance with PN-EN-ISO/IEC 17025 should contain at least the information given below

title (e.g. “Test report”);
name and address of the laboratory,
accreditation symbol and number (Example Fig. 2)
place of performance of laboratory activity;
unique identification ensuring that all its elements are recognised as part of a complete report, and unique identification of the end of the report;
name and contact data of the client;
identification of the method applied;
description, unique identification and, if necessary, condition of the object;
date of receipt of the object for testing
date of performance of the laboratory activity;
date of issue of the report;
statement that the results relate only to the objects tested
test results together with measurement uncertainties
additions, deviations or limitations of the method
identification of the person authorising the report;
clear identification of results provided by external suppliers;

Every report should be marked with a statement that the report should not be reproduced other than in full without the laboratory’s consent, which guarantees that fragments of the report will not be used separately from context. All data declared and originating from the client should be uniquely identified.

Tests performed within the accreditation granted by the Polish Centre for Accreditation (PCA is a signatory of ILAC MRA) are covered by a licence to use the international ILAC MRA mark for mutual recognition of test reports issued by accredited laboratories worldwide. Accredited laboratories of ILAC MRA signatories may use the ILAC MRA mark (Fig. 3) in combination with the accreditation symbol (Example Fig. 4) to which the accredited body is entitled.

TESTS CONCERNING OPERATING CHARACTERISTICS

Operating tests of heat pumps performed in accordance with the requirements of PN-EN 14511-4 and PN-EN 15879-1 include e.g. testing of the application range specified by the manufacturer, testing with closed heat transfer fluid flow, testing with complete power supply failure, checking operation of the defrost system, assessment of condensate drainage. The equipment should be suitable for start-up and/or operation within the limits of use (temperatures and flows) specified by the manufacturer.

TIGHTNESS AND STRENGTH TESTS OF THE INSTALLATION

Heat pumps should meet the requirements of Directive 2014/68/EU concerning the making available on the market of pressure equipment, the so-called PED Directive. Tightness and strength tests of heat pump installations are performed according to standards PN-EN 378-2, PN-EN 14276-1, PN-EN 14276-2.

Standard PN-EN 378 consists of four parts (PN-EN 378-1, PN-EN 378-2, PN-EN 378-3, PN-EN 378-4) and is the basic standard for refrigeration installations and heat pumps. It contains requirements concerning safety and environmental protection, including basic requirements, definitions, classification and selection criteria (part 1), requirements for design, construction, testing, marking and documentation (part 2), requirements concerning location of installations and personal protection (part 3), operation, maintenance, repair and recovery (part 4). This standard defines requirements for the safety of persons and property, provides guidance on environmental protection and establishes procedures for operation, maintenance and repair of refrigeration installations and recovery of refrigerants.

The PN-EN 378 series of standards contains a number of principles that must be met in order to confirm requirements resulting from applicable regulations. This is necessary inter alia when confirming fulfilment of PED directive requirements.

Tests performed when confirming PED directive requirements are:

pressure tightness test
pressure strength test

Pressure values for the above tests are determined on the basis of the maximum allowable pressure value specified by the manufacturer for the given design and intended use of the equipment.

According to the PED Directive “maximum allowable pressure PS” means the maximum pressure for which the equipment is designed, specified by the manufacturer and defined at a location specified by him, which is the location of connection of safety or limiting devices or the top of the equipment or, if this is not appropriate, any specified point”

ACOUSTIC TESTS OF HEAT PUMPS

An extremely important issue is noise emission from equipment. For space heating heat pumps this parameter is determined in accordance with PN-EN 12102-1, and for water heaters with a heat pump in accordance with PN-EN 12102-2.

One method of determining noise emission is measurement of sound pressure level on the basis of which sound power level is determined. The measured sound pressure level depends on the position of the measuring instrument, environmental conditions
and the distance between the measurement point and the sound source, and therefore is not a reliable criterion for assessing loudness. Sound power level, on the other hand, is the total acoustic energy produced by the equipment; this value corrected according to the A-weighting takes into account the sensitivity of the human ear to sounds of different frequencies. In connection with the above, particular attention should be paid to whether declared values are not understated by giving sound pressure values instead of sound power.

The sound power level of space heaters with a heat pump and combination heaters with a heat pump according to Commission Regulation (EU) No 813/2013 should not exceed the following values:

Rated heat output ≤ 6 kW	Rated heat output > 6 kW and ≤ 12 kW	Rated heat output > 12 kW and ≤ 30 kW	Rated heat output > 30 kW and ≤ 70 kW
Sound power level (L_WA) indoors 60 dB	Sound power level (L_WA) indoors 65 dB	Sound power level (L_WA) indoors 70 dB	Sound power level (L_WA) indoors 80 dB
Sound power level (L_WA) outdoors 65 dB	Sound power level (L_WA) outdoors 70 dB	Sound power level (L_WA) outdoors 78 dB	Sound power level (L_WA) outdoors 88 dB

`ELECTRICAL SAFETY OF USE TESTS OF HEAT PUMPS`

These tests focus on assessing features of the equipment enabling it to be classified as safe for use. They consist of tests checking equipment operation under controlled and abnormal conditions. Additionally assessment covers inter alia mechanical strength, resistance to high temperature, use of components, correctness of earthing connections. Tests are performed in accordance with PN-EN IEC 60335-1 taking into account detailed requirements contained in PN-EN IEC 60335-2-40. The standard concerns reasonably foreseeable hazards arising during operation of heat pumps. The standard takes into account refrigerants of groups A1, A2L, A2 and A3 according to the classification defined
in ISO 817 and detailed requirements concerning use of flammable refrigerants increasingly used in heat pumps (e.g. R290 – propane). If technical requirements are not covered by this standard, taking into account the annexes, requirements for safety of use are contained in ISO 5149.

ELECTROMAGNETIC COMPATIBILITY TESTS

No heat pump placed on the market should cause excessive electromagnetic disturbances in relation to other equipment operating in that environment. In order to verify correct operation, electromagnetic compatibility (EMC) tests are required. Equipment before being put into service and placed on the market is subject to conformity assessment with the guidelines of Directive 2014/30/EU.

SUMMARY

Placing heat pumps on the market involves a number of obligations on manufacturers or entities placing products on the market. Responsible entities seek to confirm their declarations by performing tests in independent laboratories accredited in the methodology contained in the standards. Application of standardised test methods objectifies equipment assessment and enables comparison of parameters (inter alia heating capacity, energy consumption, COP, SCOP, ηs,h) of different heat pumps under the same operating conditions. Tests in accredited bodies benefit all market participants, who thereby receive reliable information about products and the possibility of reliable verification of equipment parameters.

Authors:
MSc Eng. Dorota Niedojadło
Central Refrigeration Centre “COCH” in Kraków

MSc Eng. Mateusz Głąb
Central Refrigeration Centre “COCH” in Kraków

MSc Eng. Mikołaj Ostrowski
Central Refrigeration Centre “COCH” in Kraków

Bibliography:

L. Bednarczyk, D. Niedojadło, B. Szczepański. Accredited heat pump testing – benefits for manufacturers and users. Chłodnictwo i Klimatyzacja 2018 vol. 22, No. 11, pp. 34-36. Available at: COCH home page (accessed 28.11.2024).
PN-EN 14825:2022-11 Air conditioners, liquid chilling packages and heat pumps with electrically driven compressors for space heating and cooling -- Testing and rating at part load conditions and calculation of seasonal performance.
PN-EN 14511-1:2023-02 Air conditioners, liquid chilling packages and heat pumps for space heating and cooling and process chillers, with electrically driven compressors -- Part 1: Terms and definitions.
PN-EN 14511-2:2023-02 Air conditioners, liquid chilling packages and heat pumps for space heating and cooling and process chillers, with electrically driven compressors -- Part 2: Test conditions.
PN-EN 14511-3:2023-02 Air conditioners, liquid chilling packages and heat pumps for space heating and cooling and process chillers, with electrically driven compressors -- Part 3: Test methods.
PN-EN 14511-4:2023-02 Air conditioners, liquid chilling packages and heat pumps for space heating and cooling and process chillers, with electrically driven compressors -- Part 4: Requirements.
PN-EN 15879-1:2011 Testing and rating of direct exchange ground coupled heat pumps with electrically driven compressors for space heating and/or cooling -- Part 1: Direct exchange-to-water heat pumps.
PN-EN 12102-1:2022-12 Air conditioners, liquid chilling packages, heat pumps, process chillers and dehumidifiers with electrically driven compressors -- Determination of the sound power level -- Part 1: Air conditioners, liquid chilling packages, heat pumps for space heating and cooling, dehumidifiers and process chillers.
PN-EN 12102-2:2019-06 Air conditioners, liquid chilling packages, heat pumps, process chillers and dehumidifiers with electrically driven compressors -- Determination of the sound power level -- Part 2: Heat pump water heaters.
PN-EN IEC 60335-1:2024-04 Household and similar electrical appliances -- Safety -- Part 1: General requirements.
PN-EN IEC 60335-2-40:2023-11 Household and similar electrical appliances -- Safety -- Part 2-40: Particular requirements for electrical heat pumps, air-conditioners and dehumidifiers.
PN-EN 378-1+A1:2021-03 Refrigerating systems and heat pumps -- Safety and environmental requirements -- Part 1: Basic requirements, definitions, classification and selection criteria.
PN-EN 378-2:2017-03 Refrigerating systems and heat pumps -- Safety and environmental requirements -- Part 2: Design, construction, testing, marking and documentation.
PN-EN 378-3+A1:2021-03 Refrigerating systems and heat pumps -- Safety and environmental requirements -- Part 3: Installation site and personal protection.
PN-EN 378-4+A1:2019-12 Refrigerating systems and heat pumps -- Safety and environmental requirements -- Part 4: Operation, maintenance, repair and recovery.
Directive 2009/125/EC of the European Parliament and of the Council of 21 October 2009 establishing a framework for the setting of ecodesign requirements for energy-related products.
Regulation (EU) 2017/1369 of the European Parliament and of the Council of 4 July 2017 setting a framework for energy labelling and repealing Directive 2010/30/EU.
Commission Regulation (EU) No 813/2013 of 2 August 2013 implementing Directive 2009/125/EC of the European Parliament and of the Council with regard to ecodesign requirements for space heaters and combination heaters.
Commission Delegated Regulation (EU) No 811/2013 of 18 February 2013 supplementing Directive 2010/30/EU of the European Parliament and of the Council with regard to energy labelling of space heaters, combination heaters, packages of space heater, temperature control and solar device and packages of combination heater, temperature control and solar device.
Commission Regulation (EU) No 814/2013 of 2 August 2013 implementing Directive 2009/125/EC of the European Parliament and of the Council with regard to ecodesign requirements for water heaters and hot water storage tanks.
Commission Delegated Regulation (EU) No 812/2013 of 18 February 2013 supplementing Directive 2010/30/EU of the European Parliament and of the Council with regard to the energy labelling of water heaters, hot water storage tanks and packages of water heater and solar device.
Commission Regulation (EU) 2016/2281 of 30 November 2016 implementing Directive 2009/125/EC of the European Parliament and of the Council with regard to ecodesign requirements for air heating products, cooling products, high temperature process chillers and fan coil units.
Directive 2014/68/EU of the European Parliament and of the Council of 15 May 2014 on the harmonisation of the laws of the Member States relating to the making available on the market of pressure equipment.

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Heat pump testing – test methods, scope and standards