Performance Evaluation of a Continuous Operation Adsorption Chiller Powered by Solar Energy Using Silica Gel and Water as the Working Pair

Abstract

Abstract:In the present study, dynamic analysis and performance evaluation of a solar-powered continuous operation adsorption chiller are introduced. The adsorption chiller uses silica gel and water as the working pair. The developed mathematical model represents the heat and mass transfer within the reactor coupled with the energy balance of the collector plate and the glass cover. Moreover, a non-equilibrium adsorption kinetic model is taken into account by using the linear driving force equation. The variation of solar radiation, wind speed, and atmospheric temperature along a complete cycle are considered for a more realistic simulation. Based on the case studied and the baseline parameters, the chiller is found to acquire a coefficient of performance of 0.402. The average thermal efficiency of the solar collector is estimated to be 62.96% and the average total efficiency approaches a value of 50.91%. Other performance parameters obtained are 363.8 W and 1.82 W/kg for the cooling capacity and the specific cooling power of the chiller, respectively. Furthermore, every 1 kg of silica gel inside the adsorption reactor produces a daily chilled water mass of 3 kg at a temperature of 10• C. In addition, the cooling system harnesses 25.35% of the total available solar radiation and converts it to a cooling effect.

Comparison of Different Solar-Assisted Air Conditioning Systems for Australian Office Buildings

“…Khan et al [47] found out that based on various collector areas, for Chennai city, the solar desiccant-assisted Dedicated Outdoor Air System (DOAS) integrated radiant cooling system could achieve 7.4% to 28.6% energy savings in comparison with the cooling coil-assisted DOAS radiant cooling system. In the last several decades, solar-assisted cooling technology has widely been evaluated worldwide, including solar electric cooling powered by PV [15][16][17], solar absorption cooling [18][19][20][21][22][23], solar adsorption cooling [24,25], and solar desiccant cooling [26][27][28][29][30][31][32][33][34][35]. A theoretical modelling with experimental validation studied by Nie et al [36] demonstrated that the solid desiccant cooling assisted by heat pump was more efficient than the conventional cooling system due to high efficient dehumidification capacity.…”

Performance Evaluation of a Desiccant Dehumidifier with a Heat Recovery Unit

“…3 , mass flow rate of air, kg/h, and specific humidity, kg H 2 O/kg, at the inlet and outlet of either the adsorption zone or the desorption zone, respectively. Furthermore, both the total amount of adsorption and desorption, m ads and m des , respectively, in units of g H 2 O, can be obtained by performing the following integral of the adsorption rate and the desorption rate, respectively, over the measured period of time:…”

“…Silica gel is one of the common adsorbents because of its numerous advantages such as larger pores, larger surface area, and excellent dehumidification capability [1]. In fact, desiccant devices using silica gel as an absorbent have been widely used for dehumidification in many industrial areas [2] in addition to its use in air conditioning systems coupling with a heat source [3][4][5].…”

Experimental and theoretical performance analysis of the silica gel, LiCl with water, methanol multifunction adsorption system

“…For example, silica gel-water is one of the most common working pairs. [2][3][4][5] However, the main disadvantage of this working pair is its low adsorption capacity: under the working conditions of air conditioning, the cycled adsorption capacity is about 8% to 9% kg/kg. In order to improve the adsorption performance of silica gel, L.G.…”