Standards Development

Scope

This document applies to air-to-air air conditioners and heat pumps.

This document deals with test methods, test conditions, required measurement and calculation methods for determining capacity ratings and seasonal performance factors for heating and cooling including native control evaluation while minimizing the discrepancy between rating seasonal efficiency and average field performance.

This document provides specific requirements for load-based testing and/or CVP (standard loading, required measurements, calculations, and controls). 

Purpose

AC and HP occupy a large portion of energy consumed in buildings. Improving the energy efficiency of them is critical to mitigate climate change and to reduce energy consumption.

Several reports suggest that the current rated seasonal performance of AC and HP according to ISO 16358 and such is not representative for the average operation of the systems in the field.

The current testing standards do not test with native controls. In order to be more representative of the real world performance, new procedures are required. The ambient temperature in the field typically varies 10 degrees in a morning or more. That means the air-conditioning load is varying. AC and HP should control their capacity to match this changing load, but current test standards do not evaluate such dynamic performance of AC and HP.

Measuring uncertainty at low load conditions of AC and HP is an issue that has to be addressed in the new standard.

The new standard will provide representative test conditions and requirements for part-load testing, including, more representative load distribution, more precise operation conditions, more representative air-flow rate, more precise measurement at low load conditions. It could potentially include more precise degradation coefficient (Cd). It will provide optimized test conditions across regional differences. Application of load-based tests and/or CVP, simulation-based performance standard concept, and harmonized testing points with the building simulation will be taken into account.