Parametric Analysis of Design Parameter Effects on the Performance of a Solar Desiccant Evaporative Cooling System in Brisbane, Australia

Abstract

Solar desiccant cooling is widely considered as an attractive replacement for conventional vapor compression air conditioning systems because of its environmental friendliness and energy efficiency advantages. The system performance of solar desiccant cooling strongly depends on the input parameters associated with the system components, such as the solar collector, storage tank and backup heater, etc. In order to understand the implications of different design parameters on the system performance, this study has conducted a parametric analysis on the solar collector area, storage tank volume, and backup heater capacity of a solid solar desiccant cooling system for an office building in Brisbane, Australia climate. In addition, a parametric analysis on the outdoor air humidity ratio control set-point which triggers the operation of the desiccant wheel has also been investigated. The simulation results have shown that either increasing the storage tank volume or increasing solar collector area would result in both increased solar fraction (SF) and system coefficient of performance (COP), while at the same time reduce the backup heater energy consumption. However, the storage tank volume is more sensitive to the system performance than the collector area. From the economic aspect, a storage capacity of 30 m 3 /576 m 2 has the lowest life cycle cost (LCC) of $405,954 for the solar subsystem. In addition, 100 kW backup heater capacity is preferable for the satisfaction of the design regeneration heating coil hot water inlet temperature set-point with relatively low backup heater energy consumption. Moreover, an outdoor air humidity ratio control set-point of 0.008 kgWater/kgDryAir is more reasonable, as it could both guarantee the indoor design conditions and achieve low backup heater energy consumption.

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

“…The total conditioned area is 2003.85 m 2 and conditioned window-to-wall ratio (WWR) is 0.4. The Building Type B geometry and the zone division are shown in Figure 4 below [55]. It indicates that Darwin has the highest CDD18, followed by Brisbane, Perth, Adelaide and Sydney respectively.…”

“…The total conditioned area is 2003.85 m 2 and conditioned window-to-wall ratio (WWR) is 0.4. The Building Type B geometry and the zone division are shown in Figure 4 below [55]. The building physical properties and general modelling assumptions are listed in Table 2 [56].…”

“…When the outside air humidity ratio is under the control actuator set-point, the solar regenerative hot water pump will be off to disable the solar hot water loop so that the desiccant wheel and regeneration air heater are not in operation. This would significantly avoid unnecessary backup heater energy consumption while at the same time achieve low unmet hours during occupied cooling [55].…”

“…The SDEC system schematic diagram is demonstrated in Figure 6 below [55]. To reduce regeneration energy consumption, energy management control strategies have been applied to the system so that the desiccant subsystem is operating only when the outdoor air humidity ratio is greater than 0.008 kg/kg.…”

Optimal Dispatch of a Virtual Power Plant Considering Demand Response and Carbon Trading

“…where µ p is the energy efficiency ratio [39] for describing the relationship between the cooling effect and the electricity consumption of the chiller; µ s and µ r are the electric power conversion coefficients of storing and releasing cold energy, respectively.…”