ISO 21978:2023

Air to water heat pumps — Testing and rating at part load conditions and calculation of seasonal coefficient of performance for space heating ISO 21978:2023

Scope

This document specifies test conditions for determining the seasonal performance characteristics of air to water heat pumps for space heating with electrically driven compressors with or without supplementary heater. In the case of air to water heat pumps 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.
The seasonal coefficient of performance depends, inter alia, on the climate conditions and temperature regime of the space heating distribution network.
This document specifies:
—     three design conditions, each of them being characterized by a design temperature which represents the lowest temperature that can occur in that design condition;
—     three water temperature distribution regimes, namely “temperature application” in the text.
This document also provides a full description of three heating seasons that can be used with the associated design conditions.