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The technical and economic analysis of the dual-purpose power/water Solar Rankine Cycle (SRC) coupled with Multi-Effect Desalination (MED) system was investigated. The influence of using Thermal Va...

In the present work, a typical combined cooling, heating and power (CCHP) system comprised of boiler, flat solar collectors, absorption chiller and heat storage tank was investigated. The described system was considered to supply the given electricity, cooling and heating demand of a residential building; with heating and cooling needs of 100 and 50 kW, respectively. To find the optimum hybrid configurations with high reliability, low costs, low fuel consumption and emissions, a computer program was provided by authors in FORTRAN language. Different fuel prices were considered in the present work. The results indicated that the optimal operation strategy changes with Boiler and NGG fuel prices while it also changes with increasing the number of solar collectors, heat storage capacity and consequently decreasing total annual emission.

Abstract The present paper deals with a comparative exergo-economic analysis among four different horizontal Direct-Expansion Geothermal Heat Pumps (DX-GHP) with Carbon Dioxide ( C O 2 ) refrigerant in transcritical cycle. The studied configurations include the cycle with (a) expansion valve (EVC), (b) with expander (EC), (c) with expansion valve and Internal Heat Exchanger (EVC + IHE), and (d) with expander and IHE (EC + IHE). The unit cost of heat ($/ k W h e x ) for each configuration was determined under two scenarios of a) constant Space Heating (SH) and b) constant Domestic Hot Water (DHW) loads with the peak of 8 kW. The results showed that the lowest unit cost of heat ( c q ) and the highest total exergy efficiency ( η e x ) are associated with the (EVC + IHE) and (EC + IHE) configurations, respectively. Also, it was shown that for the SH (or DHW) load, 20% (or 14%) increase in the η e x results in 21.5% (or 20%) increase in the c q considering the electricity cost of 0.025 $/kWh. For the electricity cost of 0.25 $/kWh, however, 11% (or 20%) increase in η e x results in increasing the c q by about 7% (or 13%). It was also concluded that the configuration with the highest η e x is not that with the lowest c q .

Abstract The integration of Multi Effect Desalination (MED) unit with and without Thermal Vapor Compression (TVC) system into the Linear Fresnel Rankine Cycle (LFRC) was investigated for different seawater temperatures when it is located at the regions with different solar radiation levels. A comparison was made between the fresh water costs of the dual purpose LFRC/MED (or LFRC/MED/TVC) plants and the case when the MED and MED/TVC systems use direct steam of the LF solar field to produce fresh water (LF/MED & LF/MED/TVC). The water production costs of the described dual purpose plants were compared with that of the LFRC/Reverse Osmosis (RO) plant (LFRC/RO). An exergo-economic analysis was performed to determine the water unit costs of the plants. The results show that the fresh water costs of the LF/MED and LF/MED/TVC configurations are higher than that of the dual purpose plants. Also, it was shown that the fresh water cost is more affected by solar radiation level rather than seawater temperature of a region. It was also found that at fuel prices of 0.23$/m3, the water production costs of fuel based dual purpose plants would be equal to that of the plants with solar thermal source.

ABSTRACT The application of Linear Fresnel (LF) solar field was technically and economically considered as the thermal source of a Multi Effect Desalination Thermal Vapor Compression (MED/TVC) system with a water production rate of 9000-m3/day. The analysis was made on the five years radiation data of Kish Island, located in the Persian Gulf at south of the Iran. The water production costs were considered for three different configurations of the MED/TVC/LF desalination system to determine the required sizes of LF solar field, system costs and also amount of annual fuel savings. The results of the present study shown that the water production costs of the MED/TVC/LF system is obtained as a value between 1.63 $/m3 and 3.09 $/m3 for the systems without thermal storage and with thermal storage, respectively. The thermal storage system would increase the costs of the water production by about 42% and 65% for 6 h and 12 h of thermal storage, respectively. It was found that the water production cost of the MED/TVC/LF system with 67.77% contribution of solar energy and without the thermal storage system is high (3.32 $/m3) as compared to the conventional fossil fuel powered MED/Desalination plants with a water production cost of 1.26 $/m3.

The compound parabolic concentrators (CPCs) are of importance due to their capability in absorbing the incident solar radiation in a wide limit. The present paper deals with the optical and thermodynamic analysis of a solar CPC applying the accurate solar ray-tracing analysis. To this end, the optical efficiency of the CPC was obtained for different geometric concentration ratios ( $C_t$) based on the CPC modified equations and considering the diffuse radiation effects. The results demonstrated that the highest solar radiation absorption is obtained for $C_t$ of 1.63. The outlet temperature ( $T_o$), energy and exergy efficiencies ( $\eta _I$ and $\eta _{II}$) of the stationary evacuated tube CPC were compared with those of two different evacuated tube solar collectors without a concentrator (with large or low distance between the tubes). Based on the results, the average incident solar radiation of the CPC collector is higher than that of two other solar collectors without a concentrator. Besides, $\eta _I$ of the CPC is higher than that of other collectors within the range of effective reflective angle of the CPC, while for the higher incident angles, $\eta _I$ is lower than or equal to the other two collectors without a concentrator.

With the decrease in the fuel price subsidy in Iran, the urge for renewable energy sources to produce cooling and freshwater in a sustainable manner is becoming a challenge. Therefore, it is necessary to specify the marginal fuel price at which a solar-based cooling/water system is compatible with a fuel-based system. To this end, a solar-powered absorption refrigeration integrated with a humidification–dehumidification desalination system was thermo-economically evaluated to produce the freshwater and cooling production rates of nearly 0.58 m3/h and 28 ton/h, respectively, as well as the solar field output temperature of 175 °C. The levelized cost of product definition, which is based on the capital costs of the system, operation and maintenance costs as well as the discount rate, was used to calculate the cooling and freshwater unit of costs (COC and COW). The results demonstrated that the locations with high solar radiation levels require smaller solar field areas and larger thermal energy storage (TES) capacities, which leads to a higher percentage of annual solar share ( $$S_{{{\text{sh}}}}$$ ), and consequently lower COC and COW values. For instance, Abu Dhabi and Athens with solar radiation levels of 1977 kWh/ $${\text{m}}^{2}$$ and 1514 kWh/ $${\text{m}}^{2}$$ , respectively, have the COC (or COW) of 0.135 $/ton (or 2.88 $/m3) and 0.387 $/ton (or 7.38 $/m3), respectively. The total annual fuel saving of the proposed system with 10 h of TES for the locations with the highest and lowest $$S_{{{\text{sh}}}}$$ s [Abu Dhabi (77.97%), Athens (29.47%)] was obtained as $${1}.{38} \times 10^{6} \;{\text{m}}^{3}$$ and 0.52 $$\times 10^{6} \;{\text{m}}^{3}$$ , respectively. In addition, since the fuel price is highly subsidized in three locations of the study, the solar-based system cannot economically compete with the fuel-based system unless the fuel cost increases by 500%, 36%, and 19% for Iran, Yemen, and United Arab Emirates, respectively.

Abstract Diesel power technology has been utilized worldwide, especially in remote regions, because of its low initial capital cost. But it has negative effects on the surrounding environment and causes global warming. On the other hand, depleting oil and fuel resources has made it inevitable to seek alternative/renewable energy resources. In Iran, the cost of fuel is highly subsidized. If Iran removes the fuel subsidy, the cost of diesel fuel would increase and the photovoltaic (PV) or hybrid PV/diesel systems would become more attractive. Hybrid photovoltaic/diesel/battery (PV/diesel/bat) systems which use PV energy, combined with diesel generation power and battery bank storage are an excellent solution to decrease diesel generator costs, pollution, and electrification of remote rural areas. In this article, a study using PV/diesel/bat power systems to meet typical load requirements in a remote region in Kerman, Iran is investigated under four different diesel generator fuel price scenarios. A simple o...