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Research of solid-gas reacting media and of intercalation compounds used in suitable structures of reactors to improve the performances and spheres of use of chemical heat pumps, cooling machines and thermal transformers

Objective

Improve understanding of gas-solid couples, in particular for graphite reacting salt mixtures and graphite intercalation compounds. Develop a 1 kW AHP unit for air conditioning with a COP of 1,6; a 1 kW unit for heating which transforms heat from 80-100 C to 180 C and a solar refrigeration unit.

Until now solid gas absorption heat pumps did not find many applications due to a number of inherent disadvantages. A major problem is the low heat transfer between grains of solid material and between these grains and the heat exchanger surface. This leads to large and expensive heat exchangers and a low heat power density. Recent R&D by CNRS and INP lead to an interesting concept which may solve this problem. Another obstacle is the fact that continuous operation is not possible: batch type operation of this AHP however has the advantage the heat can be stored without extra cost. Solid gas AHP have the advantage that heat can be produced at much higher temperature levels (200-300 C) than for conventional heat pumps (150 C); this could increase the field of heat pump applications, in particular in industrial processes.

Work on solid-gas couples will be concentrated on identifying and characterizing new couples in particular for low, medium and high temperature zones, which are presently not covered by know solid- gas couples (FPM, INPG and CNRS). Heat and mass transfer will be improved by mixing the reaction salt with an inert expoilated graphite binder (CNRS) and by intercalating graphite of the reactive molecule in the form of a graphite intercalation compound (INPG). Simulation models for coupled heat transfer of these two options will be established (CNRS).

Three types of solid-gas AHP will be built to prove their technical feasibility:

An air conditioning unit of 1 kW with a COP of 1,6 which consists of four reactors with three different types of salt and which has a system of internal heat recovery (CNRS).

A single stage heat transformer of 1 kW which transforms heat of 80-100 C into a smaller amount of heat at 180 C without any other heat input (FPM).

Modify an existing solar refrigeration unit where CaCl2/NH3 will be replaced by expanded graphite - reacting salt mixtures which are expected to give a much better performance.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE
Address
Avenue Gustave Coriolis 42, C.n.r. Mtttorologique
31057 Toulouse
France

Participants (5)

Centre National de la Recherche Scientifique (CNRS)
France
Address

91406 Orsay
Faculté Polytechnique de Mons
Belgium
Address
9,Rue Houdain
7000 Mons
Institut National Polytechnique de Grenoble
France
Address
1130,Rue De La Piscine
38402 Saint-martin-d'hères
TECHNICAL UNIVERSITY OF DENMARK
Denmark
Address
Anker Engelundsvej 1, Building 101
2800 Lyngby
UNIVERSITE CATHOLIQUE DE LOUVAIN
Belgium
Address
Place De L'universite 1
Louvain-la-neuve