Ecodesign requirements for chillers and liquid chiller testing according to PN-EN 14511

Ecodesign requirements aim to harmonise energy-consumption rules across the entire territory of the Union for many types of equipment – including liquid chillers – and thereby contribute to better functioning of the internal market and to improved environmental performance of these products. Detailed guidelines for this product group are set out in: 1. Commission Regulation (EU) 2015/1095 of 5 May 2015. This Regulation sets requirements for process chillers as well as professional refrigerated storage cabinets, blast cabinets, and condensing units. 2. Commission Regulation (EU) 2016/2281 of 30 November 2016 for air heating products, cooling products, high-temperature process chillers and fan coil units. At Central Refrigeration Centre “COCH” in Kraków, testing is performed on all of the equipment types referred to here. This paper provides information on testing of process chillers and comfort chillers intended for space air conditioning. These units are best known under the name “chilled water units” (chillers); in the literature and standards one also finds the terms “liquid chillers” (e.g. on the PKN website, standards in the PN-EN 14511-1:2018 series are titled “Air conditioners, liquid chilling packages and heat pumps for space heating and cooling and process chillers, with electrically driven compressors”) or “liquid coolers”. Basic definitions: process chiller means a product that combines at least one compressor and one condenser, capable of cooling and continuously maintaining a low or medium temperature of a liquid intended for cooling equipment or a refrigeration system; it may integrate a condenser, refrigerant circuit accessories or other auxiliary equipment; low temperature means that the process chiller is capable of delivering its rated cooling capacity when the outlet temperature of the indoor heat exchanger is −25°C, under standard rating conditions; medium temperature means that the process chiller is capable of delivering its rated cooling capacity when the outlet temperature of the indoor heat exchanger is −8°C, under standard rating conditions; high temperature means that the process chiller is capable of delivering its rated cooling capacity when the outlet temperature of the indoor heat exchanger is 7°C, under standard rating conditions; rated cooling capacity, expressed in kW, means the cooling capacity that the process chiller is able to deliver at full load and measured under standard rating conditions at a reference ambient temperature of 35°C for air-cooled units and at a condenser water inlet temperature of 30°C for water-cooled units; comfort chiller means a cooling product: a) whose indoor heat exchanger (evaporator) extracts heat from a water-based cooling system (heat source) designed to operate at a chilled-water outlet temperature equal to or higher than 2°C; b) that is equipped with a cooling source; and c) whose outdoor heat exchanger (condenser) rejects that heat to a heat sink (or sinks) such as ambient air, water or ground. The above definitions appear in the regulations and are analogous to those in the PN-EN 14511 series of standards; however, it should be noted that in the latest version translated into Polish slightly different terms were used for naming the equipment. Liquid chillers with heat recovery condenser (definition according to PN-EN 14511-1) – a factory-made assembly intended for liquid cooling and for heat recovery, i.e. use of waste heat from the unit(s) performing primarily the cooling function, either by means of an additional heat exchanger (e.g. a liquid chiller with an additional condenser) or by transferring heat from the refrigeration system for use in equipment performing primarily a heating function.

Test conditions according to PN-EN 14511

Tables 1–5 present the test conditions according to PN-EN 14511-2 for various types of liquid chillers. NOTE: Units with a remote condenser are tested using a water- (brine-) cooled condenser whose characteristics allow the required chiller operating conditions to be achieved.

Measurement methodology

Determination of cooling capacity Cooling capacity is determined from measurement of the water volume flow rate and its temperatures at the inlet and outlet of the unit, taking into account the specific heat capacity and density. During measurements, permissible deviations must be observed (Table 6). Cooling capacity is calculated from the relationship (on the left). Heat recovery capacity is determined using the formula shown below (on the right). Determination of effective power input The average power input should be determined from the integrated electrical power over the same data collection period as that used to determine cooling capacity and heat recovery capacity. When determining these values, the power drawn by liquid pumps must be taken into account; this power is determined using the relationships given in the standard, taking into account the difference in external or internal static pressure depending on whether the pump is an integral part of the unit or not. The procedure and calculation algorithm are given in Part 3 of the standard under discussion. For units with a remote condenser, the power drawn by the auxiliary liquid pump for the remote condenser should not be included in the effective power input of the unit. The standard specifies requirements for measurement accuracy and for the measuring equipment used.

COCH accredited testing laboratory

The Refrigeration Equipment Laboratory of Central Refrigeration Centre “COCH” in Kraków Sp. z o.o. tests refrigeration, air-conditioning and heat-pump equipment, including the chillers discussed above. We operate in accordance with the requirements of PN-EN ISO/IEC 17025. Chiller testing performed at COCH is covered by accreditation of the Polish testing laboratory system (Polish Centre for Accreditation accreditation No. AB 308) and by a licence to use the international ILAC MRA mark on mutual recognition of test reports issued by accredited laboratories worldwide. The laboratory has several test chambers enabling testing of equipment over a wide capacity range. Basic technical data of one of the test chambers (schematic diagram shown in Figure 1):

• dimensions: 26 × 4 × 6 m
• temperature control range from −30 to 50°C;
• humidity control range from 10 to 98% RH;
• airflow velocity control.

The scope of testing may include determination of: total cooling capacity; moisture flow condensed from air by the unit under test; electrical energy consumption of the unit; air volume flow rate; water pressure difference at the inlet and outlet of the unit; supply voltage and frequency; energy efficiency ratio EER; seasonal energy efficiency ratio SEER; seasonal space cooling energy efficiency ηs,c; seasonal energy performance ratio (SEPR). Additional measurements and tests according to PN-EN 14511: operating range test; start-up test; test under extreme operating conditions; shut-off of heat transfer media flow; total power supply failure; additional non-standard test conditions selected by the client; starting current measurement; high and low pressure measurement in the refrigeration circuit; other additional tests and measurements. REFERENCES: Commission Regulation (EU) 2015/1095 of 5 May 2015 implementing Directive 2009/125/EC of the European Parliament and of the Council with regard to ecodesign requirements for professional refrigerated storage cabinets, blast cabinets, condensing units and process chillers. Commission Regulation (EU) 2016/2281 of 30 November 2016 implementing Directive 2009/125/EC of the European Parliament and of the Council establishing a framework for the setting of ecodesign requirements for energy-related products, with regard to ecodesign requirements for air heating products, cooling products, high-temperature process chillers and fan coil units. PN-EN 14511-1:2018-08. PN-EN 14511-2:2018-08. PN-EN 14511-3:2018-08. PN-EN 14511-3:2018-08. PN-EN 14511-2:2009. www.pkn.pl accessed 28.05.2021 Authors: Dorota NIEDOJADŁO, MSc Eng., Bogdan SZCZEPAŃSKI, MSc Eng.