Solar heating and cooling by a thermochemical process. First experiments of a prototype storing 60 kW h by a solid/gas reaction

• Published in: Solar energy Vol. 82; no. 7; pp. 623 - 636
• Main Authors: Mauran, S., Lahmidi, H., Goetz, V.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.01.2008; Elsevier; Pergamon Press Inc
• Subjects: Air conditioning. Ventilation; Applied sciences; Chemical heat pump; Chemical reactions; Composite consolidated reactive layer; Cooling; Energy; Energy. Thermal use of fuels; Equipments, installations and applications; Exact sciences and technology; Experiments; Heating; Heating, air conditioning and ventilation; Modular solid–gas reactor; Natural energy; Prototypes; Solar energy; Solar thermal conversion; Storage; Techniques, equipment. Control. Metering; Storage; Chemical heat pump; Modular solid–gas reactor; Composite consolidated reactive layer; Air conditioning; Strontium bromide; Solar collector; Prototype; Modular solid-gas reactor; Buildings; Solar heating; Solar cooling systems; Thermodynamics; Environment impact; Refrigerant fluid
• ISSN: 0038-092X; 1471-1257
• DOI: 10.1016/j.solener.2008.01.002

The chemical heat pumps using monovariant solid/gas reactions and thermal solar energy are potentially interesting for the air-conditioning of building (heating in winter or mid-season and refreshing in summer). They provide a function of storage without loss and potentially at high energy density. The selected reaction involves SrBr 2 as reactant and H 2O as refrigerant fluid. It is adapted to the thermodynamic constraints in temperature (heat provided by plane solar collector, heating and cooling on the level of the floor) and uses reagents having a weak impact for the environment and health. The reactive salt SrBr 2 is implemented with an expanded natural graphite in the form of a consolidated material which has acceptable thermal conductivity and permeability adapted to low pressure. The prototype reactor has a total volume of 1 m 3. It is able to store, with a complete reaction, 60 kW h or 40 kW h for the heating or cooling function respectively. This prototype was tested under conditions representative of summer or mid-season; the mean heating or cooling powers, typically about 2.5–4 kW, are still insufficient because of a low heat transfer at the interface between the reactive layer and the exchanger wall. However this limitation can be clearly attenuated; that is the subject of current work in following these first experiments.