Zhileng xuebao (Jan 2025)
Study on the Multi-energy Complementary Absorption Heat Pump Applied for Combined Cooling and Heating with Large Temperature Zone
Abstract
Under the background of carbon neutrality, it is of great importance to realize low-carbon combined cooling and heating supply in distributed areas away from centralized cooling and heating network. In this paper, a combined cooling and heating system based on absorption heat pump is proposed, which uses a variety of clean and renewable energy such as solar heat, geothermal, waste heat, biomass and air-source energy to achieve the combined cooling and heating in a wide temperature zone of -20-100℃, suitable for distributed areas such as villages, cities and industrial parks. The system model is constructed based on Aspen, and a prototype is set up. The prototype uses vacuum tube collector to capture solar thermal energy, and introduces natural gas secondary combustion to balance load fluctuations of solar energy. Through the medium circulation and valve switching, multiple sets of indoor heating/cooling ends can be driven by a single set of absorption heat pump and outdoor unit. Environmental test of the prototype was performed in Jinan, and during the whole testing period the solar thermal ratio could reach 35%. Through gas proportional regulation, all-weather stable energy supply was achieved. Moreover, a wide range of concentration adjusting was realized by level control of solution tank, so that the system can operate efficiently in a wider temperature zone. It was found that the COP of cooling reached 0.30-0.43 at -20℃, and 0.70-0.78 at 7℃, with cooling water temperatures varies from 30 to 20℃; and the COP of heating reached 1.40-1.90 at 45℃, and 1.35-1.56 at 80℃, with evaporation temperature varies from -15 to 20℃. It was showed that by introducing solar thermal driving and ambient energy recovery, the proportion of renewable energy of the system was over 50%. Compared with the traditional method of gas furnace plus air conditioning, the annual operating cost and carbon emission of the proposed system was reduced by over 54.3% and 44%, respectively, which has great application potential.
