Experimental study of a diesel engine heat pump in heating mode for domestic retrofit application

Abstract

An engine driven heat pump (ENHP) can provide better efficiency compared to electric heat pump (EHP) considering primary energy consumption. The present work aimed to find suitability of diesel engine heat pump as a domestic retrofit application for off or weak gas/electricity network area. For this project work, water-to-water heat pump test facility was developed which consisted heat pump, diesel engine and heat recovery arrangements. The system performance was evaluated for 65°C flow temperature from condenser at three different engine speeds (1600, 2000 & 24000 rpm) and four evaporator water inlet temperature (0, 5, 10 & 15°C). The system performance was evaluated by heating capacity, isentropic efficiency, coolant heat recovery, exhaust gas heat recovery and PER. Performance analyses showed that heat recovery contributed 33% in total heat output where heat recovery was in a range of 1.7 to 3.7 kW. PER varied in the range of 0.9 to 1.4 showing good potential in terms of 35-65% primary energy saving and 23-42% CO 2 emissions reduction compared to conventional system. DEHP optimisation showed ability to meet water flow temperature requirement of 65-73°C by speed variations and heat recovery providing good potential to meet heating demand during winter and summer periods in retrofit settings.

Experimental study on cooling performance and energy saving of gas engine-driven heat pump system with evaporative condenser

“…Kamal et al [20] investigated the field performance of gas engine driven heat pumps used in a commercial buildings. Shah et al [21] developed a water-to-water gas engine heat pump system. The results showed that the heat recovery contributed 33% in total heat output and the PER varied in the range of 0.4-1.4.…”

Performance analysis of diesel engine heat pump incorporated with heat recovery

“…In order to assess DEHP performance for better capacity control, experiments data were matched with house heating demand at respective temperature. A case for retrofit application at 65°C flow temperature has been already presented by Shah et al [30]. In summer month, with 35C flow temperature, almost all-heating demand can be met by heat recovery.…”

“…It provides information for various flow temperature required for conventional radiator (high temperature), medium temperature and underfloor heating system. The study on high temperature application (65°C flow temperature) for retrofit application has been shown by author's previous work [30]. This paper presents detailed work related to flow temperature, engine speeds and their comparative analysis at respective evaporation temperature conditions.…”

Analysis on field trial of high temperature heat pump integrated with thermal energy storage in domestic retrofit installation

“…They concluded that larger floor area, part load operation (oversized heat pump) and parasitic losses reflects in low COP compared to other European field trials and better controls, design, small houses (new) would help to improve the performance of heat pump [16]. Wu et al showed benefits of cascade heat pump integrated with TES to reduce pressure ratio at low ambient temperature [17] whereas Shah et al showed benefits of engine driven heat pump in off/weak gas/electricity network area to achieve flow temperature in range of 70°C with waste heat recovery from the engine [18] [19]. It is also noted that DHW uses 3.5 times more power compared to SH for heat pump where vast installation of heat pump in poorly insulated housing stock could considerably impact peak electricity demand in the UK [20].…”