Adsorption heat pumps using zeolites and water are currently the subject of intensive research activity because they are very attractive, especially for domestic application. Nevertheless their development is still limited by poor internal heat transfer.
The aim of the project is to integrate the water adsorption capacity of zeolites with the heat conductivity of (sintered) metal substrates and to simulate an adsorption/desorption unit of a heat pump for heating and cooling. The use of a multi-reactor adsorption system in which heat is regenerated will lead to the development of a heat pump which can be operated continuously and saves energy. It is expected that the following values will be reached:
- COP value : 1.7 - 1.9 in heating
- Cycle time: 10 - 20 min
- Heat conductivity: 50 - 100 times the value of the bed of zeolite pellets
The deliverables consist of :
- A report defining the major properties and parameters of the heat pump unit and its operation.
- A report giving the performance of existing zeolites and sintered metals in heat pump operating conditions.
- A report giving the zeolite preparation, deposition and performance in adsorption capacity and heat conductivity.
- A report containing computer codes and calculation results.
The technical feasibility of adsorption machines has been demonstrated by numerous prototypes that have been built and tested. Nevertheless, the economical optimization of these systems depends on the improvement of their specific power output which requires adsorbers with high thermal conductivity and heat exchangers well adapted to the adsorbent bed. The principal disadvantage of adsorption machines is actually connected with the poor heat transfer inside the solid porous bed and at the metal-adsorbent interface.
The use of sintered metals as structuring material for deposition of adsorbent materials should produce a strong enhancement of the thermal conductivity by which heat will easily be supplied to, and removed from the zeolites.
The zeolite-water adsorbent-adsorbate pair appears the most interesting for domestic reversible heat pump application such as space heating and refrigerating by using heat as primary energy source. It presents good characteristics both from an environmental, and an energetic point of view. In fact, zeolites and water are neither polluting, nor toxic or corrosive. Water has the highest latent heat, and it is the most environmentally friendly refrigerant. If the European industry is not able to keep up with American and Japanese developments this will lead to the loss of the heat pump market. Therefore, the expertise of three European research institutes was combined to develop a novel adsorption heat pump based on metalsupported zeolites. GASTEC (Apeldoorn, NL) being project coordinator provides expertise in gas technology to the gas industry (catalysis and reactor design). The CNR-TAE institute (Messina, I) research activities concern the transformation and storage of energy by chemical processes (adsorption processes in reversible heat pump systems).
Technical University Delft (Delft, NL) has more than 15 years experience with zeolite synthesis, modification and application. Since 5 years the growth of zeolites on supports is investigated.
Funding SchemeCSC - Cost-sharing contracts
2628 BL Delft