Experimental Study of Three-Bed Adsorption Chiller with Desalination Function

Abstract

Energy efficiency is one of the most important topics nowadays. It is strictly related to energy demand, energy policy, environmental pollution, and economic issues. Energy efficiency can be increased and operating costs reduced by using waste heat from other processes. One of the possibilities is to use sorption chillers to produce chilled water and desalinated water. Low-temperature waste heat is not easy to utilize because of the low energy potential. Using adsorption chillers in low-temperature conditions allows utilizing waste heat and producing useful products in many regions of the world. The paper presents the results of an experimental study carried out on a three-bed adsorption chiller with desalination function, using silica gel and water as a working pair. The laboratory test stand included one evaporator, one condenser, and three separate tanks for water, desalinated water, and brine, respectively. The test stands scheme and description were presented. All results were obtained during several test hours with stable temperature conditions in the range of 57–85 °C for the heating water. It is found that the Coefficient of Performance (COP) increased from 0.20 to 0.58 when the heating water temperature increased from 57 to 85 °C. A similar finding is reported for Specific Cooling Power (SCP), which increased from 27 to 160 W/kg as the heating water temperature increased from 57 to 85 °C. It can be concluded that the heating water temperature strongly impacts the performance of the adsorption chiller.

The Effects of Using Steam to Preheat the Beds of an Adsorption Chiller with Desalination Function

“…As a result, when the heating water inlet temperature increased from 55 • C to 95 • C, the chiller COP increased by up to 80%. A similar result was obtained experimentally by Sekret and Turski [33], as well as Sztekler et al [18]. Sekret and Turski [33] found that the chiller COP increased by 17% when the heating water inlet temperature increased from 80 • C to 95 • C, while Sztekler et al [18] reported a COP improvement of 190% when the heating water inlet temperature increased from 57…”

“…The solution to the first problem, i.e., the discontinuity in the operation of adsorption chillers, is the use of two- [11], three- [18], four- [19] or even six-bed chillers [20]. On the other hand, efforts to improve the COP and SCP include many different methods, some of which only consist in changing the operating conditions of the device, and some require interference with the construction of the chiller.…”

“…The simplest methods of improving the COP and SCP of adsorption chillers, which do not require modification of the chillers' structure, are the selection of the appropriate time of the adsorption/desorption cycles [21], or the use of a heat source with a higher temperature [18]. However, it should be kept in mind that the heat supplying adsorption chillers is usually waste heat with a given temperature, which usually cannot be changed.…”

Theoretical Investigation of Vapor Transport Mechanism Using Tubular Membrane Distillation Module

“…Using waste heat from other operations can improve energy efficiency and save operating costs. One option is to utilize sorption chillers to generate cooled and desalinated water [ 9 ].…”

Experimental Investigation of an Intensified Heat Transfer Adsorption Bed (IHTAB) Reactor Prototype

“…Hygroscopic structure, strongly developed specific surface area, adsorption/desorption in the required temperature regime enabling the use of low-temperature thermal energy sources and large participation of micropores in the porous structure of silica gel guarantee compatibility with water as an adsorbate. Moreover, being an environmentally friendly refrigerant, water provides a desalination functionality of the considered prototype [46,47]. The spherical and irregular type of silica gel was examined in fluidized bed conditions.…”