MAKALE/ ARTICLE in TRNSYS-simulations a single effect and also a double effect absorption ehiller, both available on the market, were investigated in combination with various sizes of parabolic trough collector fields. For the COP (Coefficient of Performance) of the double effect ehiller from the company Broad (catalogue dala) as a function of load see Figure 1. 50000 45000 40000 35000 60% load 80% 100% Change of COP values as a Function of Load of Double Effect Absorption Chiller ■ Solar Field :2 30000 · ■Back-Up System --······· oHeat to ACM c 25000 52 20000 15000 10000 5000 o Jan Feb Mar Apr Flgure 2 Simulation Results for Single Effect ACM and 150 m2 Solar Field - Monthly Energy Rates Solar Field, Back-Up System and Heat to ACM ·····- CI Solar Field ...... ■ Back-Up System ·························-···--··-···-··-··················· □Heat to ACM Flgure 3 Simulation Results for Double Effect ACM and 150 m2 Solar Field - Monthly Energy Rates Solar Field, Back-Up System and Heat to ACM By using weather data for Antalya (in the south of Turkey) and consumers' data in one hour resolution, the hourly ECOGENERATION WORLD outputs of the solar array (including piping) and of the ACM were calculated for the cooling season between 15th of April and 30th of September. The solar field is connected to a tank and from there to a heat exchanger. in case of the double effect ACM this is a steam generator. lf the solar field or tank cannot deliver heat anymore, a back-up firing supplies the heat, as long as cooling has to be provided according to the load profile. The solar field output is based on efficiency dala of the parabolic trough collector of lndustrial Solar Technology (1ST), USA as measured at DLR [3]. The COP for the single effect ACM was setto O.72, the COP of the double effect ACM was implemented as a function of load (Fig. 1 ), with an average COP of 1.5 (obviously part load between 40 - 70% is the dominant load situation in this simulation). The single effect machine is driven with hot water of 110°C inlet and 80°C outlet temperature. As the temperature drop in the heat exchanger was neglected, solar field temperatures are equal. The double effect ACM needs saturated steam at 4 bar (144°C). Because the solar field does not directly deliver steam, a steam generator has to be implemented, causing solar field temperatures of 150°C inlet and 180°C outlet. Figures 2 and 3 show the monthly energy rates necessary for the ACMs as well as the energy rates of solar field and back up firing. in this simulation the solar field size was assumed to be 150 m2 and in summer a cooling output of 33000 kWh per month (16500 kWh in April) had to be supplied by the ACM. As can be expected, the high temperature level in the solar field supplying the double effect ACM leads to lower annual energy yields from the solar field of 565 kWh/m2*a, compared to 760 kWh/m2*a for the single effect ACM (represented by the "Solar Field" columns). The solar heat (and the heat from the back-up firing) is used more efficient by the double effect ACM though, which therefore needs less heat to produce the requested amount of cooling. This effect more than compensates the lower solar field output and overall results in a higher cooling output from solar heat. Less back-up firing in case of the double effect ACM is needed, as first the solar heat is converted into a higher amount of cooling and second the back-up firing is converted more efficiently. The columns "Back-Up System" show the monthly amount of back-up firing. The columns "Heat to ACM" describe the summarised amount of heat from solar field and back-up system to the ACM. Since the back-up system delivers heat complementary to the solar field, their total sum should be as high as the amount of heat delivered to the ACM. Some energy is lost by the tank though, so not all solar energy reaches the ACM. Provided the assumed COP's of the cooling machines can be reached in practice, the solar field can be reduced by
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