Prices of energy are shown in Table 2. Table 2. Prices of energy. Hefei is taken as an example. Figures 2 — 4 show the results of energy consumption simulation of the PV cooling system and the solar absorption cooling systems in Hefei. The abscissa represents the period from 1 June to 30 September.
Results of energy consumption simulation of the solar single-effect absorption cooling system in Hefei. Results of energy consumption simulation of the solar double-effect absorption cooling system in Hefei. The energy consumption is low in some days of July and August because the rainy season in Hefei is in July and August.
In the rainy season, the air temperature and the solar irradiation are both low, so the cooling load of the building is also low. The total energy consumption of the compression chiller is 2. This is because the EER of the vapor compression chiller is much higher than that of the single-effect Li-Br absorption chiller and the double-effect Li-Br absorption chiller.
Other vital simulation results are shown in Table 3. Table 3. Results of energy consumption simulation. The equipment costs of three kinds of cooling systems are shown in Figure 5. It can be observed that the costs of the same kind of cooling systems are similar. And the cost of the solar single-effect absorption cooling system is the highest among the others. In Hefei, for example, the cost of the solar single-effect absorption cooling system is thousand yuan, which is 2.
The cost of the double-effect absorption cooling system is a little lower than that of the solar single-effect absorption cooling system, which is thousand yuan. Though the chiller of the solar single-effect absorption cooling system is cheaper than that of the solar double-effect absorption cooling system, the solar single-effect absorption cooling system needs more collectors than the solar double-effect absorption cooling system.
And the cost of the PV cooling system is thousand yuan, which is higher than the conventional compression cooling system of thousand yuan. Figure 6 shows the percentages of costs of equipment parts in Hefei. The costs of collectors are the major costs of the solar single-effect absorption cooling system and the solar double-effect absorption cooling system, which separately account to And the cost of PV panels is the major cost of the PV cooling system, which accounts to So, it can be inferred that the price movements of collectors and PV panels have a big effect on the result of economic comparison.
For comparison, when we calculated the energy generations of the PV system and the collectors, we only counted the energy generation during the cooling period rather than the whole year.
Figures 7 — 9 , respectively, show the annual cooling costs in Hefei, Chengdu and Haikou. Costs comparison of the PV cooling system and the solar absorption cooling system in Hefei. Costs comparison of the PV cooling system and the solar absorption cooling system in Chengdu.
Costs comparison of the PV cooling system and the solar absorption cooling system in Haikou. Figures 7 — 9 show that the costs of solar absorption cooling are higher than the costs of PV cooling in all three areas.
Even though the PV subsidies are not counted, the economic performance of PV cooling is also better than that of solar absorption cooling. In Hefei, the annual cost of the solar single-effect absorption cooling is thousand yuan, which is 2.
Also in Hefei, the annual cost of the solar double-effect absorption cooling system is thousand yuan, which is 1. So in Hefei, the minimum annual cost of the solar absorption cooling is 1. In Chengdu, the minimum annual cost of the solar absorption cooling is 1. And in Haikou, the minimum annual cost of the solar absorption cooling is 1. The price of gas has an effect on the cost of solar absorption cooling. The price of electricity has an effect on the cost of solar PV cooling and the conventional vapor compression cooling.
So, the relations between the energy prices and the economic performance of cooling technologies are discussed. Considering the positive correlation between the electricity price and the desulfurized-coal online electricity price, we assume that the desulfurized-coal online electricity price changes with proportion to the electricity price. Figure 10 shows the annual costs of PV cooling and solar absorption cooling under different gas prices, electricity prices and the desulfurized-coal online electricity prices in Hefei.
The abscissa represents the ratio of assumed electricity price to the real electricity price. Annual costs of PV cooling and solar absorption cooling under different energy prices in Hefei.
Figure 10 shows that the cost of PV cooling is lower than the cost of solar absorption cooling despite the changes of energy prices. When the energy prices vary, the minimum annual cost of solar absorption cooling is thousand yuan, which is 1.
When considering the annual costs of the solar PV cooling and the solar absorption cooling, we count the whole year power generation of the PV system. Figures 11 — 13 , respectively, show annual cooling costs in Hefei, Chengdu and Haikou.
Costs comparison of the PV cooling system and the conventional compression cooling system in Hefei. Costs comparison of the PV cooling system and the conventional compression cooling system in Chengdu.
Costs comparison of the PV cooling system and the conventional compression cooling system in Haikou. Figures 11 — 13 show that PV cooling not only has better economic performance than conventional compression cooling but also can create a big economic benefit. In Hefei, Chengdu and Haikou, the maximum annual net income of PV cooling are, respectively, thousand yuan, 52 thousand yuan and thousand yuan.
In Hefei, Chengdu and Haikou, the annual costs of the conventional vapor compression cooling are , respectively, 81 thousand yuan, 67 thousand yuan and thousand yuan, which are , respectively, 3. These results can indicate that PV cooling without PV subsidies is better in economic performance than conventional compression cooling. With the assumption that the desulfurized-coal online electricity price changes with proportion to the price of electricity, the relations between the price of electricity and the economic performance of cooling technologies are discussed.
The results are shown in Figures 14 — The abscissa also represents the ratio of assumed electricity price to the real electricity price. Annual costs of PV cooling and conventional vapor compression cooling under different energy prices in Hefei.
Annual costs of PV cooling and conventional vapor compression cooling under different energy prices in Chengdu. Annual costs of PV cooling and conventional vapor compression cooling under different energy prices in Haikou.
Figures 14 — 16 show that electricity price and desulfurized-coal online electricity price have a strong influence on the economic compression of PV cooling and conventional vapor compression cooling. When electricity price and desulfurized-coal online electricity price drop, the cost of conventional vapor compression cooling will reduce, and the cost of PV cooling increases.
And such a big reduction of energy prices is nearly impossible. So, PV cooling has a good economic performance now. And with the continued decline of the PV cells price, the economic performance of PV cooling will be better in the future. So, it is a good choice to use the PV cooling system. Table 4 shows the summary of economic analysis. Table 4. Summary of economic analysis results. Based on the conditions of Hefei, Chengdu and Haikou, the energy consumptions of the solar PV cooling system, the solar absorption cooling system and the conventional vapor compression cooling system are simulated.
The conclusions are shown below. In Hefei, Chengdu and Haikou, the economic performance of PV cooling is better than that of solar absorption cooling and conventional vapor compression cooling. Even if PV subsidies are not counted, the economic performance of PV cooling is also better than that of solar absorption cooling and conventional vapor compression cooling. In Hefei, Chengdu and Haikou, the minimum annual costs of the solar absorption cooling are respectively 1.
And in Hefei, Chengdu and Haikou the annual costs of the conventional vapor compression cooling are respectively 3. In some areas where the solar energy resource is not poor, even if the energy prices change a lot, the economic performance of PV cooling will also be better than that of solar absorption cooling and traditional vapor compression cooling. In Hefei, when the energy prices vary, the minimum annual cost of solar absorption cooling is 1. Sarbu I , Sebarchievici C.
The equipment uses completely harmless working fluids. The maximum cooling load can be achieved with the maximum available solar radiation and hence potential of the refrigeration system.
Maintenance costs are lower due to fewer moving parts like solenoid valves and vacuum pumps. It is almost noiseless system, where there are not many moving parts, other than the solution pump in the absorption refrigeration systems. Taking advantage of solar thermal plants in the sorption refrigeration technology even when there is no heat demand.
Operation costs are lower due to low electricity consumption in comparison with vapor compression systems. The desiccant air-conditioning system utilizes the capability of desiccant materials in removing the air moisture content by sorption process. All materials that attract moisture at different capacities are called desiccant [ 4 ]. The desiccant cooling system can be a suitable selection for thermal comfort especially in climates with high humidity.
Moreover, this technique allows us to utilize renewable energy or low-temperature gains from solar energy, waste heat, and cogeneration to drive the cooling cycle. The comparison between desiccant system and conventional systems is listed in Table 1. Two configurations were described in detail below: ventilation and recirculation modes. The schematic of the ventilation mode representation is demonstrated in Figure 6a.
On the conditioning side of the system air processing side , warm and humid air enters the slowly rotating desiccant wheel and is dehumidified by adsorption of water 1—2. Since the air is heated up by the adsorption heat, a heat recovery wheel is passed 2—3 , resulting in a significant precooling of the supply air stream.
Subsequently, the air is humidified and thus further cooled by a controlled humidifier 3—4 according to the set-values of supply air temperature and humidity. In order to control the sensible heat factor, the remix air is introduced by the mix evaporatively cooled room air with the cooled and dried room make-up air 5—6. On the regeneration side of the system, the exhaust air stream of the rooms is humidified 6—7 close to the saturation point to exploit the full cooling potential in order to allow an effective heat recovery 7—8.
Finally, the cold and humid air is exhausted to the atmosphere 9—10 and the cooling cycle is completed. Schematic of desiccant cooling system in a ventilation mode and b recirculation mode.
The recirculation mode representation is depicted in Figure 6b. It uses the same components as the ventilation mode except the process air side in the recirculation mode is a closed loop, whereas the regeneration air side is an open cycle where the outdoor air is used for regeneration.
A solar-driven ejector cooling system consists of an ejector cooling cycle and a collector circuit. The main components of the system are collector array, generator, ejector, condenser, expansion valve, evaporator, and cycle pump. A schematic diagram of the solar ejector cooling system and its component is presented in Figure 7. The working principle of the ejector systems follows the below states [ 24 , 25 ]:. Schematic presentation of the solar ejector cooling configuration.
In the generator, the refrigerant is vaporized as a primary steam by utilizing the solar energy coming from the solar collector. This primary steam leaves the generator at a relatively high pressure and enters the supersonic nozzle of the ejector to accelerate it at supersonic velocity and creating low pressure at the nozzle exit section. This low pressure draws the secondary flow coming from the evaporator into the chamber.
The primary and secondary streams are mixed in the mixing chamber. These mixing steams enter into diffuses where increases its pressure to the condensing pressure. The mixing stream discharges from the ejector to the condenser, where the stream is converted into liquid refrigerant by rejection heat to the surrounding.
Some part of the liquid refrigerant pumps to the generator and the remaining liquid part leaves the condenser and enters the evaporator through expansion value.
In expansion value, the refrigerant pressure is dropped and this refrigerant enters the evaporator to absorb heat from space that required to cool and the refrigerant is converted into vapor and enters to the ejector. One of the promising methods that utilize solar heat to produce mechanical work and then use it to drive a conventional vapor compression cycle is solar Rankine cooling systems. Two different configurations of solar Rankine cooling systems were suggested by different scholars [ 26 ].
One arrangement is using separate power and cooling system where the compressor of the vapor compression cycle is mechanically coupled with the expander of organic Rankine cycle. Another arrangement is an integrated system by the use of one joint condenser for both cycle coupled with the expander-compressor. The main advantages of a second configuration are the use of a same working fluid in both loops to remove a leakage and mixing problems.
Moreover, the integrated design is simpler but on the other side reduces the system flexibility. Figure 8 depicts a schematic for two widely solar Rankine cooling system arrangements. In the first loop of organic Rankine cycle, high-pressure liquid coming from the pump is vaporized inside the boiler state 1 that absorbs the heat from solar collector. The vapor state 2 enters the expander and produces a useful work which is used to drive a compressor of a conventional refrigeration cycle.
The working fluid pressure from the expander outlet is same to the condenser pressure state 3. After that, a rejection heat to the surrounding inside the condenser converts the working fluid to saturated fluid.
Subsequently, a pressure of the working fluid is increased by using pump to enter a boiler as subcooled liquid state 1. Representation of a Rankine solar cooling system as a separate configuration for power and refrigeration cycles and b integrated configuration for power and refrigeration cycle.
The executed investigations on the field of solar thermal-driven cooling systems and the gained results can be concluded as follows: The investigations on solar thermal-driven systems show that solar thermal refrigeration systems are promised technologies, especially in the small and middle cooling capacity ranges.
The higher is the required chilled water temperature, the higher are the refrigeration capacity and the coefficient of performance COP of the absorption refrigeration machine. The lower is the cooling water temperature; the higher are the refrigeration capacity and the COP of the absorption refrigeration machine. Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution 3.
Help us write another book on this subject and reach those readers. Login to your personal dashboard for more detailed statistics on your publications. Edited by Ibrahim H. We are IntechOpen, the world's leading publisher of Open Access books. Stored rainwater is pushed into a ramp at the edge of the panels. Water then flows onto the surface of the modules and immediately lowers the temperature. The water only spreads across the glass surface of the panels and does not touch any plastic parts, such as the backsheets or other components.
The system is set in motion by a temperature sensor which triggers the water spread when ambient temperatures exceed 25 C. The cooling systems collect the water from a rainwater tank. And after the water is used, it can be recycled, filtered, and stored again.
So far, the technology has only been adopted in projects backed by cost-offsetting incentives. However, the company claims that it has started to sharply lower the cost structure of its systems to support unsubsidized projects in the near future.
For a 10 MW PV plant, around 25 km in pipes would be needed, which complicates logistics and installation, Boutteau said. Sunbooster currently needs to send teams out to install its systems. However, the company plans to train partners who are capable of deploying its technologies at a global level, in line with its standards. He added that the adoption of a similar cooling system could increase the complexities of projects and the number of possible variables.
This content is protected by copyright and may not be reused. If you want to cooperate with us and would like to reuse some of our content, please contact: editors pv-magazine. More articles from Emiliano Bellini. I suppose there could be the added benefit of keeping the panels clean during low rain periods, such as summer, likely where part of the efficiency increase comes from. My son did electronic project for his 7th std to spray water when temperatures sensor is activated by fire.
Other was clap activated sensor. But for precision an arduino or raspberry microprocessor TI or others will help to be accurate.
Cheap too. Pipe part only may be costly. If possible it could be hidden if using drip irrigation type cheaper pipes. Using it to run an evaporative cooler with more expensive BME for humidity sensing. Great educational opportunities. Hi Nice to see that people are trying to get more yield from PV system by designing such solutions. As you said the it will affect light emission to cells but it will offset by temperature reduction of modules, then whats the benefit of using that.. Rather it costs and definitely will also need to replace filters to have clean water for modules.
Additional cost.. How much will be cost benefit ratio and will it be feasible for residential systems. The quantity and speed of the cooling water must be defined and specified.
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