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It is well known that the energy consumption of refrigerating and air-conditioning units is as high as heating systems. It is also clear that cooling loads and availability of solar radiation are approximately in phase. Turkey is located in an ideal position to benefit from solar energy for not only water-heating but also cooling. The use of solar powered absorption refrigerating and air-conditioning systems will save energy, especially in the summer season. The contribution of these systems to the Turkish energy sector and, consequently, to the economy will be considerably high. In this study, a combined water-heating and cooling system based on absorption refrigeration was designed and constructed. The system consists of four flat plate collectors, an evaporator, an absorber, a generator, a condenser, a solution pump and two heat exchangers. Each part was custom designed to provide 4000 kcal/h cooling load. In this system, a mixture of R22 and DMETEG (DiMethyl Ether Tetra Ethylene Glycol) is used as the working fluid. The R22, which has a less damaging effect on the ozone layer compared to other CFCs, was employed as refrigerant. The thermodynamic results of the experimental system were compared with theoretical calculations, and a reasonably good agreement was found. The results show that the present system is efficient and effective.

It is well known that the energy consumption of refrigerating and air-conditioning units is as high as heating systems. It is also clear that cooling loads and availability of solar radiation are approximately in phase. Turkey is located in an ideal position to benefit from solar energy for not only water-heating but also cooling. The use of solar powered absorption refrigerating and air-conditioning systems will save energy, especially in the summer season. The contribution of these systems to the Turkish energy sector and, consequently, to the economy will be considerably high. In this study, a combined water-heating and cooling system based on absorption refrigeration was designed and constructed. The system consists of four flat plate collectors, an evaporator, an absorber, a generator, a condenser, a solution pump and two heat exchangers. Each part was custom designed to provide 4000 kcal/h cooling load. In this system, a mixture of R22 and DMETEG (DiMethyl Ether Tetra Ethylene Glycol) is used as the working fluid. The R22, which has a less damaging effect on the ozone layer compared to other CFCs, was employed as refrigerant. The thermodynamic results of the experimental system were compared with theoretical calculations, and a reasonably good agreement was found. The results show that the present system is efficient and effective.

The energy base of urban settlements requires greater integration of renewable energy sources. This study presents a “hydrogen city” model with two cycles at the district and building levels. The main cycle comprises of hydrogen gas production, hydrogen storage, and a hydrogen distribution network. The electrolysis of water is based on surplus power from wind turbines and third-generation solar photovoltaic thermal panels. Hydrogen is then used in central fuel cells to meet the power demand of urban infrastructure. Hydrogen-enriched biogas that is generated from city wastes supplements this approach. The second cycle is the hydrogen flow in each low-exergy building that is connected to the hydrogen distribution network to supply domestic fuel cells. Make-up water for fuel cells includes treated wastewater to complete an energy-water nexus. The analyses are supported by exergy-based evaluation metrics. The Rational Exergy Management Efficiency of the hydrogen city model can reach 0.80, which is above the value of conventional district energy systems, and represents related advantages for CO2 emission reductions. The option of incorporating low-enthalpy geothermal energy resources at about 80 °C to support the model is evaluated. The hydrogen city model is applied to a new settlement area with an expected 200,000 inhabitants to find that the proposed model can enable a nearly net-zero exergy district status. The results have implications for settlements using hydrogen energy towards meeting net-zero targets.

The energy base of urban settlements requires greater integration of renewable energy sources. This study presents a “hydrogen city” model with two cycles at the district and building levels. The main cycle comprises of hydrogen gas production, hydrogen storage, and a hydrogen distribution network. The electrolysis of water is based on surplus power from wind turbines and third-generation solar photovoltaic thermal panels. Hydrogen is then used in central fuel cells to meet the power demand of urban infrastructure. Hydrogen-enriched biogas that is generated from city wastes supplements this approach. The second cycle is the hydrogen flow in each low-exergy building that is connected to the hydrogen distribution network to supply domestic fuel cells. Make-up water for fuel cells includes treated wastewater to complete an energy-water nexus. The analyses are supported by exergy-based evaluation metrics. The Rational Exergy Management Efficiency of the hydrogen city model can reach 0.80, which is above the value of conventional district energy systems, and represents related advantages for CO2 emission reductions. The option of incorporating low-enthalpy geothermal energy resources at about 80 °C to support the model is evaluated. The hydrogen city model is applied to a new settlement area with an expected 200,000 inhabitants to find that the proposed model can enable a nearly net-zero exergy district status. The results have implications for settlements using hydrogen energy towards meeting net-zero targets.

Abstract The dynamics of isolated-photon plus two-jet production in pp collisions at a centre-of-mass energy of 13 TeV are studied with the ATLAS detector at the LHC using a dataset corresponding to an integrated luminosity of 36.1 fb−1. Cross sections are measured as functions of a variety of observables, including angular correlations and invariant masses of the objects in the final state, γ + jet + jet. Measurements are also performed in phase-space regions enriched in each of the two underlying physical mechanisms, namely direct and fragmentation processes. The measurements cover the range of photon (jet) transverse momenta from 150 GeV (100 GeV) to 2 TeV. The tree-level plus parton-shower predictions from Sherpa and Pythia as well as the next-to-leading-order QCD predictions from Sherpa are compared with the measurements. The next-to-leading-order QCD predictions describe the data adequately in shape and normalisation except for regions of phase space such as those with high values of the invariant mass or rapidity separation of the two jets, where the predictions overestimate the data.