Versatile siloxane based adsorbent coatings for fast water adsorption processes in thermally driven chillers and heat pumps

2015 ◽  
Vol 85 ◽  
pp. 1-8 ◽  
Author(s):  
Harry Kummer ◽  
Gerrit Füldner ◽  
Stefan K. Henninger
Keyword(s):  
Water Adsorption ◽  
Heat Pumps ◽  
Thermally Driven ◽  
Adsorption Processes

scholarly journals New Experimental Installation to Determine Adsorptive Properties of Magnesium Sulphate

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5652
Author(s):  
Oscar Banos ◽  
Sven Ohmann ◽  
Cornelia Breitkopf
Keyword(s):  
Thermal Management ◽  
Heat Pumps ◽  
Critical Factors ◽  
Adsorption Refrigeration ◽  
Two Factors ◽  
Adsorption Processes ◽  
Material Separation ◽  
Adsorption Desorption ◽  
Adsorptive Properties ◽  
Desorption Capacity

Adsorption processes are of great interest in catalysis, material separation, and thermal management. In recent decades, adsorbents have been further investigated because of their applications in adsorption refrigeration, heat pumps, and thermal energy storage. Thus, there is an increasing need to determine the macroscopic properties of the adsorbent, specifically their adsorption/desorption capacity and speed, because these two factors determine the power and size of the corresponding adsorber. Many designs have been proposed, but there is still not a generally adopted technology for the analysis of those properties. In this paper, a novel instrument is described, which is capable of determining the macrokinetic properties of an adsorbent composite, with better control and higher accuracy than gravimetric, volumetric, or barometric installations, and lower price and complexity than spectroscopic installations. The design of the installation is detailed, highlighting the main challenges and critical factors. The two working modes of the installation are described, and one example is provided and analyzed for each of them.

Performance Analysis of a Silica Gel-Water Adsorption Cooler: Impact of Nanofluids on Cooler Performance and Size

2015 ◽  
Author(s):  
I. P. Koronaki ◽  
M. T. Nitsas ◽  
E. G. Papoutsis ◽  
V. D. Papaefthimiou
Keyword(s):  
Heat Transfer ◽  
Silica Gel ◽  
Cooling Capacity ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Theoretical Research ◽  
Adsorption Chiller ◽  
Heat Transfer Fluids ◽  
Thermally Driven ◽  
Sorption Heat

Thermally driven chillers also known as sorption heat pumps have drawn considerable attention in recent years. They can be divided into two main categories: absorption (liquid-vapor) and adsorption (solid-vapor) systems. Even though adsorption cycles have relatively lower coefficient of performance compared to absorption cycles, however they prevail in terms of heat source, electric consumption for moving parts, crystallization etc. In order to overcome the drawback of low COP and specific cooling capacity, nanofluids, i.e. mixtures of nanometer size particles well-dispersed in a base fluid, can be used as heat transfer fluids as recent experimental and theoretical research has proved that nanofluids can exhibit a significant increase on heat transfer. In this study a two bed, single-stage adsorption chiller which utilizes the silica gel-water pair as adsorbent-refrigerant is simulated. The cooling capacity and the COP of the chiller are calculated for various cycle times. The usage of nanofluids as heat transfer fluids in the chiller evaporator and condenser and their effect on chiller performance and size is investigated. It is proved that the presence of nanofluids at different volume concentrations will enhance the cooling capacity and the COP of the adsorption chiller and therefore will lead to smaller, in terms of size, heat exchangers.

scholarly journals Crystals for sustainability – structuring Al-based MOFs for the allocation of heat and cold

CrystEngComm ◽  
2015 ◽  
Vol 17 (2) ◽  
pp. 281-285 ◽  
Author(s):  
M. F. de Lange ◽  
C. P. Ottevanger ◽  
M. Wiegman ◽  
T. J. H. Vlugt ◽  
J. Gascon ◽  
...  
Keyword(s):  
Water Adsorption ◽  
Heat Pumps ◽  
Adsorption Behaviour

The special water adsorption behaviour of CAU-10-H makes it ideal for application in adsorption driven heat pumps and chillers.

scholarly journals Improvement of Commercial Active Carbon for Use in an Adsorption Cooling System

2003 ◽  
Vol 21 (1) ◽  
pp. 1-8 ◽  
Author(s):  
B. Buczek ◽  
L. Czepirski ◽  
E. Komorowska-Czepirska
Keyword(s):  
Active Carbon ◽  
Cooling System ◽  
Particle Surface ◽  
Heat Pumps ◽  
Methanol Adsorption ◽  
Heat Effects ◽  
Adsorption Processes ◽  
Adsorption Cooling System ◽  
Successive Removal

Of the various gas/solid adsorption processes, the adsorption of methanol on active carbon seems to be most interesting for use in thermodynamic systems such as heat pumps and transformers, as well as in cooling systems. The porous structures of two series of active carbons modified by the successive removal of the external layers from the particle surface, one by abrasion in a spouted bed and the other by subsequent demineralization of the abraded particles, were evaluated on the basis of nitrogen and methanol adsorption data. The porous structure parameters for these two sorbate series agreed reasonably well and allowed the D–R approach to be usefully applied for the characterization of these systems. The methods for calculating the heat effects associated with methanol adsorption over wide ranges of temperature and pressure are discussed.

Modeling and Experimental Investigation of an Oil-Free Microcompressor-Turbine Unit for an Organic Rankine Cycle Driven Heat Pump

2014 ◽  
Vol 137 (3) ◽  
Author(s):  
Jonathan Demierre ◽  
Antonio Rubino ◽  
Jürg Schiffmann
Keyword(s):  
Turbine Unit ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Heat Pumps ◽  
Tip Clearance ◽  
Vapor Compression ◽  
Heating And Cooling ◽  
Vapor Compression Cycle ◽  
Compression Cycle ◽  
Thermally Driven

Domestic heating and cooling will more and more have to rely on heat pumps (HPs) in order to support a more rational use of primary energy consumption. The HP market is mainly dominated by electrically driven vapor compression cycles and by thermally driven sorption processes. The drawback of electrically driven vapor compression cycle is their dependence on an electrical grid and the fact that they increase the winter or summer electricity peak demands. Hence, a thermally driven vapor compression cycle would offer substantial advantages and flexibility to the end user for heating and cooling applications. This paper presents the investigation of an oil-free compressor-turbine unit (CTU) used for a thermally driven HP (TDHP) based on the combination of a HP compression cycle and an organic Rankine cycle (ORC). The CTU consists of a radial inflow turbine and a centrifugal compressor of the order of 2 kW each, directly coupled through a shaft supported on gas lubricated bearings. The CTU has been tested at rotor speeds in excess of 200 krpm, reaching compressor and turbine pressure ratios up to 2.8 and 4.4, respectively, and isentropic efficiencies around 70%. Comparisons between the experimental data and predictions of models, that are briefly described here, have been carried out. A sensitivity analysis based on the experimentally validated models shows that tip clearance, for both compressor and turbine, and surface roughness of the compressor are key parameters for further improving performance.

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