An Integrated Heat Recovery Air-Conditioning System (IHRACS) with double-heating series-wound heat pump part 1: Scheme and performance

Remaining heat accumulates in underground commercial space, because of its special building envelope, the earth. Although exhaust air heat recovery is popularly adopted in air-conditioning systems to make use of it, there is still plentiful potential on heat recovery. This paper brought up an integrated heat recovery air-conditioning system (IHRACS) with double-heating series-wound heat pump, which mainly consists of water chillers, air-handling units (AHU), air-source heat pumps (ASHP), high temperature water-to-water heat pumps (WWHP), etc. In this system, not only waste heat/cool in exhaust air is recovered by ASHPs, but also condenser heat of chillers by WWHPs. For each part of the system, including water chiller, high temperature WWHP and ASHP, quasi-dynamic modelling based on each thermal balance state was implemented respectively. Based on these and the fact of an underground shopping center in Harbin, China, energy performance was calculated under year-round air-conditioning load in summer, winter and transition season respectively. According to year-round simulation result, IHRACS consumes electricity by 40.6 kWh/m², and saves equivalent primary energy by 393 MJ/m² compared to a conventional system (electric chiller + AHU), besides domestic hot-water supply. Furthermore, it's believed that this system can be applied in most cities in China, with a potential of saving more energy than in Harbin.