High temperature cooling and low temperature heating in buildings of EBC Annex 59

Abstract

Using a low supply water temperature in heating conditions and a high water temperature during cooling can increase energy efficiency, use renewable energy sources, and provide a comfortable and healthy indoor climate. High temperature cooling and low temperature heating is achieved by reducing temperature difference in heat transfer and energy transportation process. The losses in temperature difference can be classified into three types: by heat/moisture exchange; by energy transportation through air/water circulation; by indoor terminal that releases heat/cooling to indoor conditioned space. The air handling process of HVAC system and indoor terminals are the key factor of reducing temperature difference. Aiming at the losses in HVAC system, Annex 59, titled High Temperature Cooling & Low Temperature Heating in Buildings, is a new international cooperative work under the framework of International Energy Agency (IEA) Energy in Buildings and Communities (EBC). This paper introduces the background, scope, objective, structure and deliverables of Annex 59. Annex 59 will try to present a new perspective and a new concept to analyze HVAC system in buildings. The goal of the Annex is to build up new concept of analyzing HVAC system from the perspective of reducing mixture loss and transfer loss and then apply it in high temperature cooling and low temperature heating system.