Combined Cooling And Power System Research Articles

Comprehensive analysis and parametric optimization of a CCP (combined cooling and power) system driven by geothermal source

A CCP (combined cooling and power) system, which integrated a flash-binary power generation system with a bottom combined cooling and power subsystem operating through the combination of an organic Rankine cycle and an ejector refrigeration cycle, was developed to utilize geothermal energy. Thermodynamic and exergoeconomic analyses were performed on the system. A performance indicator, namely the average levelized costs per unit of exergy products for the overall system, was developed to assess the exergoeconomic performance of the system. The effects of four key parameters including flash pressure, pinch point temperature difference in the vapor generator, inlet pressure and back pressure of the ORC turbine on the system performance were evaluated through a parametric analysis. Two single-objective optimizations were conducted to reach the maximum exergy efficiency and the minimum average levelized costs per unit of exergy products for the overall system, respectively. The optimization results implied that the most exergoeconomically effective system couldn't obtain the best system thermodynamic performance and vice versa. An exergy analysis based on the thermodynamic optimization result revealed that the biggest exergy destruction occurred in the vapor generator and the next two largest exergy destruction were respectively caused by the steam turbine and the flashing device.

Assessment of off-design performance of a small-scale combined cooling and power system using an alternative operating strategy for gas turbine

A small-scale combined cooling and power (CCP) system usually serves district air conditioning apart from power generation purposes. The typical system consists of a gas turbine and an exhaust gas-fired absorption refrigerator. The surplus heat of the gas turbine is recovered to generate cooling energy. In this way, the CCP system has a high overall efficiency at the design point. However, the CCP system usually runs under off-design conditions because the users’ demand varies frequently. The operating strategy of the gas turbine will affect the thermodynamic performance of itself and the entire CCP system. The operating strategies for gas turbines include the reducing turbine inlet temperature (TIT) and the compressor inlet air throttling (IAT). A CCP system, consisting of an OPRA gas turbine and a double effects absorption refrigerator, is investigated to identify the effects of different operating strategies. The CCP system is simulated based on the partial-load model of gas turbine and absorption refrigerator. The off-design performance of the CCP system is compared under different operating strategies. The results show that the IAT strategy is the better one. At 50% rated power output of the gas turbine, the IAT operating strategy can increase overall system efficiency by 10% compared with the TIT strategy. In general, the IAT operating strategy is suited for other gas turbines. However, the benefits of IAT should be investigated in the future, when different gas turbine is adopted. This study may provide a new operating strategy of small scale gas turbine to improve the off-design performance of CCP system.

Solid oxide fuel cell application in district cooling

This paper presents analysis of the performance of a combined cooling and power (CCP) system for district cooling. The cogeneration system is designed to provide cooling for a low-rise residential district of 27,300 RT (96 MWc). A solid oxide fuel cell (SOFC) generates electric power to operate chillers, and the exhaust fuel and heat from the SOFC run gas turbines and absorption chillers. Thermal energy storage is utilized to reduce system capacity. Part-load operation strategies target maximizing energy efficiency. The operation of the system is compared through an hourly simulation to that of packaged air-conditioning units typically used to cool homes. The CCP system with the district cooling arrangement improves the cooling-to-fuel efficiency by 346%. The peak power requirement is reduced by 57% (24 MW) and the total fuel energy is reduced by 54% (750 TJ y−1). The system cuts annual carbon dioxide emissions to less than half and reduces other harmful emissions. A cost analysis of the system components and operation resulted in a 53% reduction in the cost per ton-hour of cooling over traditional systems.

Development of Combined Cooling and Power System with NH3-H2O Absorption Cycle Driven by Solar Energy

In recent years, a combined cooling and power system (CCPS) with NH3-H2O absorption cycle has been aroused great interests. The previous researches on CCPS have been reviewed to summarize the properties of working pair and the experimental apparatus and demonstration devices firstly. Then, a new CCPS driven by solar energy has been developed and discussed.

When downtime is a disaster [CHP for Internet service providers

As Internet traffic grows and more business is done on-line, many service providers and large companies are turning to third parties who can house their mission-critical servers in specialised facilities with secure power supplies, computer grade air conditioning and adequate protection against fire and intruders. One company, 186k Ltd, has opted for packaged combined cooling and power (CCP) plant at two of its telehouses. It has signed contract with Lattice Energy Services (LES), which will finance, own and operate the plant under the 20-year agreement, and provide electricity and cooling to 186k with suitable guarantees of performance and reliability. The primary energy source at both sites is the CCP system, sized to meet peak demand even with one engine on standby. This n+1 configuration means that planned maintenance and minor breakdowns can be accommodated without resorting to the back-up supply. This combined heat and power technology provides secure, cost-effective electricity and air conditioning for the telehouses.