Unified thermodynamic model to calculate COP of diverse sorption heat pump cycles: Adsorption, absorption, resorption, and multistep crystalline reactions
2019 (English)In: International journal of refrigeration, ISSN 0140-7007, E-ISSN 1879-2081, Vol. 99, p. 382-392Article in journal (Refereed) Published
Abstract [en]
A straightforward thermodynamic model is developed in this work to analyze the efficiency limit of diverse sorption systems. A method is presented to quantify the dead thermal mass of heat exchangers. Solid and liquid sorbents based on chemisorption or physical adsorption are accommodated. Four possible single-effect configurations are considered: basic absorption or adsorption (separate desorber, absorber, condenser, and evaporator); separate condenser/evaporator (two identical sorbent-containing reactors with a condenser and a separate direct expansion evaporator); combined condenser/evaporator (one salt-containing reactor with a combined condenser/evaporator module); and resorption (two sorbent-containing reactors, each with a different sorbent). The analytical model was verified against an empirical heat and mass transfer model derived from component experimental results. It was then used to evaluate and determine the optimal design for an ammoniate salt-based solid/gas sorption heat pump for a space heating application. The effects on system performance were evaluated with respect to different working pairs, dead thermal mass factors, and system operating temperatures. The effect of reactor dead mass as well as heat recovery on system performance was also studied for each configuration. Based on the analysis in this work, an ammonia resorption cycle using LiCl/NaBr as the working pair was found to be the most suitable single-effect cycle for space heating applications. The maximum cycle heating coefficient of performance for the design conditions was 1.50 with 50% heat recovery and 1.34 without heat recovery.
Place, publisher, year, edition, pages
Elsevier Ltd , 2019. Vol. 99, p. 382-392
Keywords [en]
Ammonia, Analytical, Dead thermal mass, Heat recovery, Resorption, Sorption heat pump, Adsorption, Evaporators, Heat pump systems, Lithium compounds, Mass transfer, Separation, Sorbents, Space heating, Thermodynamic properties, Waste heat, Waste heat utilization, Direct expansion evaporators, Heat and mass transfer models, Heating coefficients, Operating temperature, Sorption heat pumps, Thermal mass, Coefficient of performance
National Category
Energy Engineering
Identifiers
URN: urn:nbn:se:mdh:diva-42697DOI: 10.1016/j.ijrefrig.2018.12.021ISI: 000461334900038Scopus ID: 2-s2.0-85060929731OAI: oai:DiVA.org:mdh-42697DiVA, id: diva2:1289023
2019-02-152019-02-152020-10-22Bibliographically approved
In thesis