# Concentrating Solar Collectors for a Trigeneration System--A Comparative Study
## 1 Introduction
This system is fed by PTCs and a biomass boiler, while heating is produced in two temperatures (low and medium levels). They calculated the energy and exergy efficiency values at 51.3% and 21.8%, respectively. Moreover, they concluded that the investment is sustainable with a payback period of about 5 years. A comparative study of different configurations of trigeneration systems [18] coupled with a PTC proved that the connection of an absorption chiller in the ORC condenser is the best technique, and the separate use of the ORC and an absorption chiller is the second, while the connection of a vapor cooling compression cycle to the ORC turbine is the less efficient choice. In another work, [PERSON] et al. [19] tried to use a PTC in a Brayton-Rankine combined cycle in order to reduce fuel consumption. According to their results, it is found that the cost of the produced power can be 22% lower with the exploitation of the solar irradiation. The utilization of Linear Fresnel reflectors (LFR) has been examined by [PERSON] et al. [20]. More specifically, they examined a system with (LFR) coupled with a thermal photovoltaic absorber for heating and power production. Moreover, this unit included a storage tank, an absorption machine and heat exchanging surfaces. They found that the yearly production of electricity, cooling and heating is 2.29, 3.94 and 6.53 MWh, respectively. Another literature study with an LFR-based trigeneration system has been conducted by [PERSON] et al. [21]. They designed a system of 45 kW electricity power which also produces heating and cooling, while its main devices are a Rankine power block, absorption chiller, adsorption chiller and cooling towers. [PERSON] et al. [22] found that the integration of LFR in a Brayton-Rankine combined cycle leads to a levelized cost of electricity close to USD 0.06/kWh, an overall plant efficiency at 80%, and the solar share reaches close to 10%. The use of solar dishes (SD) has been investigated by [PERSON] et al. [23] in a unit with a Brayton cycle, an organic Rankine cycle and an absorption machine for desalination, heating and electricity production. They calculated the energy and exergy efficiencies at 28.4% and 27%, respectively, while the daily fresh water production was 1.5 m\({}^{3}\) at 70 \({}^{\circ}\)C. They compared their system with a Kalina cycle for electricity production, and they generally found similar efficiencies; the Kalina cycle has lower energy efficiency and higher efficiency. However, they stated that the multigeneration system is more efficient because it can cover more energy needs and not only electricity production. Moreover, in another literary work, [PERSON] and [PERSON] [24] studied a unit with solar dishes and a biomass boiler which includes a Brayton cycle, fuel-cell, absorption chiller and gasifier, while the useful products are cooling, electricity and hydrogen. The energetic and energetic efficiencies were calculated at 40% and 27%, respectively. [PERSON] and [PERSON] [25] studied a system with solar dishes coupled with the Stirling engine, PTC, solid oxide fuel cell and desalination unit. The useful outputs of this system are hydrogen, fresh water and electricity, while the system energy efficiency is around 19% and the daily water production is 8.5 m\({}^{3}\). Lastly, there are some studies with solar towers in trigeneration systems. [PERSON] and [PERSON] [26] studied a system with a solar tower, Rankine cycle, absorption chiller, distillation unit and back-up boiler which produces fresh water, electricity and cooling power. According to their results, this trigeneration system presents system energy efficiency at 35%. In another work, with a tower in the trigeneration system, [PERSON] et al. [27] studied the combination of a Rankine cycle to a Brayton cycle for electricity, heating and cooling production with energy and exergy efficiencies at 67% and 40%, respectively. The aforementioned literature review demonstrates the great scientific interest in the investigation of solar-driven trigeneration units.