GB 21454-2021Minimum allowable values of energy efficiency and energy efficiency grades for multi-connected air conditioning (heat pump) units (English PDF)

1 Scope

China's mandatory energy efficiency standard for multi-split air conditioning and heat pump units - the VRF systems, one outdoor unit serving many indoor units through a refrigerant loop, which have become the default way of air conditioning offices, hotels and larger apartments. It specifies the energy efficiency grades, the minimum allowable values of energy efficiency and the test methods for multi-connected air conditioning (heat pump) units, including the low static pressure ducted types. A multi-split system is the case where a full-load rating is least meaningful of all. Its whole selling point is that the outdoor unit modulates to serve whatever fraction of the indoor units happens to be calling, and in a real building that fraction is almost never one: a system is sized for every room occupied at once and then spends its life serving a third of them. The standard therefore sets the grades on the annual performance factor, a seasonal index computed over the distribution of loads and outdoor temperatures the machine actually meets over a year, rather than on a rating taken at a single design condition. That single choice is what makes the standard bite, because a machine optimised for a full-load number and one optimised for a seasonal number are different machines. The grades are tabulated by rated cooling capacity, the minimum allowable value is the threshold below which a unit may not be sold, and the test methods refer the measurement back to the product standards. Issued on 11 October 2021 and in force since 1 November 2022, it replaces GB 21454-2008.

This document specifies the energy efficiency grades, minimum allowable values of energy efficiency and test methods for multi-connected air-condition (heat pump) units and low ambient temperature air source multi-connected heat pump (air conditioning) units, as well as requirements for the implementation of the Standard. This document is applicable to multi-connected air-condition (heat pump) units (hereinafter referred to as multi-connected units) and low ambient temperature air source multi-connected heat pump (air conditioning) units (hereinafter referred to as low-temperature multi-connected units) adopting air-cooled or water-cooled condensers.

2 Normative References

The contents of the following documents constitute indispensable clauses of this document through the normative references in the text. In terms of references with a specified date, only versions with a specified date are applicable to this document. In terms of references without a specified date, the latest version (including all the modifications) is applicable to this document.

GB/T 18836-2017 Ducted Air-conditioning (heat pump) Units

GB/T 18837-2015 Multi-connected Air-condition (heat pump) Unit

GB/T 25857-2010 Low Ambient Temperature Air Source Multi-connected Heat Pump (air conditioning) Unit

3 Terms and Definitions

The terms and definitions defined in GB/T 18837-2015 and GB/T 25857-2010, and the following terms and definitions are applicable to this document.

3.1 minimum allowable values of energy efficiency for multi-connected air- condition (heat pump) units Minimum allowable values of energy efficiency for multi-connected air-condition (heat pump) units refer to the minimum allowable values of measured actual performance factor (APF), cooling seasonal energy efficiency ratio (SEER), integrated part load value (cooling) [IPLV(C)] or cooling energy efficiency ratio (EER) during the cooling and heating operation under the specified operating conditions. For single-cooling products, only the SEER is assessed.

3.2 minimum allowable values of energy efficiency for low ambient temperature air source multi-connected heat pump (air conditioning) units Minimum allowable values of energy efficiency for low ambient temperature air source multi- connected heat pump (air conditioning) units refer to the minimum allowable values of heating seasonable performance factor (HSPF) and coefficient of performance (COP) of multi- connected heat pump (air conditioning) units that adopt a motor-driven compressor and can generate hot air at an ambient temperature not lower than 25 C during the heating operation under the specified operating conditions.

3.3 energy efficiency ratio at the minimum-load operating conditions for multi- connected air-condition (heat pump) units EERmin Energy efficiency ratio at the minimum-load operating conditions for multi-connected air- condition (heat pump) units refer to the ratio of the cooling capacity to the total electric power consumption of the units when turning on an indoor unit with the minimum cooling capacity for continuous and stable cooling operation under the specified cooling capacity test conditions.

4 Energy Efficiency Grades

4.1 The energy efficiency of multi-connected units and low-temperature multi-connected units is classified into three grades, in which, Grade-1 represents the highest energy efficiency.

4.2 The energy efficiency of air-cooled single-cooling multi-connectors is classified in accordance with the measured SEER of the products. The measured SEER of each energy efficiency grade shall not be less than the stipulations of Table 1. temperature multi-connectors outdoor units with a nominal heating capacity of less than or equal to 18,000 W, the standby power shall not be greater than 15 W (additional functions that can be turned off during the test shall be turned off).

5.3 Products adopting electric auxiliary heating shall be able to manually turn on and off the electric auxiliary heating system. Meanwhile, the working status of the electric auxiliary heating system shall be indicated in an obvious position.

5.4 When the outdoor dry-bulb temperature of the multi-connectors is higher than or equal to 0 C, the electric auxiliary heating shall not be automatically turned on.

5.5 When the outdoor dry-bulb temperature of the low-temperature multi-connectors is higher than or equal to 20 C, the electric auxiliary heating shall not be automatically turned on. For the low-temperature multi-connectors whose electric auxiliary heating is selected by the user, a port is reserved for the controller, and the start and stop of the auxiliary electric heating system is controlled by the units, the method of turning on and off the auxiliary electric heating shall be explained in the instruction manual (or operation manual).

5.6 The tolerances shall satisfy the following stipulations:

a) The stated value of energy efficiency of the product shall not be less than the specified value of the index corresponding to its rated energy efficiency grade, and shall be within the value range corresponding to its rated energy efficiency grade.

b) The measured values of the SEER and EERmin of single-cooling multi-connectors, the APF and EERmin of heat-pump multi-connectors, the IPLV(C) and EER of water- cooled multi-connectors, the HSPF, COP12C and COP20C of low-temperature multi- connectors shall not be less than 95% of the stated values. The measured values and the stated values are in integral multiples of 0.01.

c) The stated nominal cooling capacity and the measured value of the multi-connectors shall be within the range of the nominal cooling capacity corresponding to its rated energy efficiency grade. The stated nominal heating capacity and the measured value of the low-temperature multi-connectors shall be within the range of the nominal heating capacity corresponding to its rated energy efficiency grade.

d) The measured cooling seasonal total energy CSTE (single-cooling) and the calculated annual power consumption APC (heat-pump) of the multi-connectors shall be less than or equal to 110% of the stated values; the measured heating seasonable total energy HSTE of the low-temperature multi-connectors shall be less than or equal to 110% of the stated value.