Exergoeconomic comparison of solar-assisted absorption heat pumps, solar heaters and gas boiler systems for district heating in Sarein Town, Iran. (5th May 2019)

• Record Type: Journal Article
• Authors: Salehi, S.; Yari, M.; Rosen, M.A.
• Is Part Of: Applied thermal engineering. Volume 153(2019)
• Page Start: 409
• Page End: 425
• Publication Date: 2019-05-05
• Subjects: Solar-assisted absorption heat pump -- Absorption compression-assisted heat pump -- Exergoeconomics -- Solar heating system -- Gas boiler; Heat engineering -- Periodicals; Heating -- Equipment and supplies -- Periodicals; Periodicals; 621.40205
• DOI: 10.1016/j.applthermaleng.2019.03.022
• Languages: English
• ISSNs: 1359-4311

Abstract

Highlights: Solar-assisted absorption heat pumps economically compared with solar heating and gas boiler systems. Geothermal hot springs are used for evaporation process and prevention of freezing. The exergy efficiency has the highest value of up to about 25% for LiBr/H2 O absorption systems. The product unit cost for solar heating system has the highest value of about 220 $/GJ in December. Gas boiler and NH3 /H2 O absorptions systems have the lowest values of product unit cost of about 25 and 40 $/GJ, respectively. Abstract: The feasibility of solar-assisted absorption heat pumps for space heating is assessed with exergoeconomics and compared with gas boilers and solar heating systems for the town of Sarein in Iran. In the study, single-effect LiBr/H2 O and NH3 /H2 O absorption and absorption compression-assisted heat pumps are analyzed for heating loads of 50–2 MW. Using the geothermal hot springs located in Sarein as heat sources for refrigerant evaporation, the problem of freezing is prevented. In addition, a multi-objective optimization is performed to specify the optimal design points considering the temperatures of the evaporator and generator as decision parameters. Simulations show that the gas boiler and the solar heating system have the lowest and second lowest values of exergy efficiency, at about 45% and 35% lower than the exergy efficiency for NH3 /H2 O absorption systems. The maximum achievable exergy efficiency for the NH3 /H2 O and LiBr/H2 O absorption systems are 0.23 and 0.25, respectively. But, the solar heating system has the highest product unit cost, mainly due to its high capital costs. The minimum obtainable product unit costs for the NH3 /H2 O and LiBr/H2 O absorption systems occur in April, and are about 22 $/GJ and 55 $/GJ, respectively.