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The operation of the ambient air conditioning systems (ACS) is characterized by considerable fluctuations of the heat load in response to the current climatic conditions. It needs the analyses of the efficiency of the application of compressors with frequency converters for refrigeration capacity regulation in actual climatic conditions. A new method and approach to analyzing the effectiveness of ACS cooling capacity adjusting by using the compressor with changing the rotational speed of the motor as an example have been developed, according to which the overall range of changeable heat loads is divided into two zones: the zone of ambient air processing with considerable fluctuations of the current heat load, that requires effective refrigeration capacity regulation by the compressor with frequency converters (from 100% rated refrigeration capacity down to about 50%) and not an adjustable zone of reduced refrigeration capacity below 50% rated refrigeration capacity of the compressor. The magnitudes of threshold refrigeration capacity between both zones are chosen according to the rational value of installed (design) refrigeration capacity on the ACS, required for cooling the ambient air to a target temperature that ensures the maximum annual refrigeration capacity production in actual current climatic conditions. The proposed method and approach to the analysis of the efficiency of the refrigeration capacity regulation of the ACS compressor by distributing the overall range of changes in current heat loads allows increasing the efficiency of utilizing the installed refrigeration capacity in prevailing climatic conditions.

The efficiency of air conditioning (AC) systems depends on the operation of their air coolers at varying heat loads in response to current changeable climatic conditions. In general case, an overall heat load of any AC system comprises the unstable range, corresponding to ambient air processing with heat load fluctuations, and a comparatively stable part for subsequent air subcooling. Following from this approach, a rational design overall heat load is chosen to provide a maximum annular refrigeration capacity generation and divided into a comparatively stable basic part and a remaining part for ambient air precooling at changeable heat loads. The ambient air precooling mode with considerable heat load fluctuation needs load modulation, whereas the comparatively stable heat load range can be covered by operation at about nominal mode. According to modern trend in AC systems the load modulation is performed by varying refrigerant feed to air coolers in Variable Refrigerant Flow (VRF) system. But with this the problem of inefficient operation of air coolers caused by dry-out of inner walls at the final stage of inside tube refrigerant evaporation followed by dropping the intensity of heat transfer remains unsolved. As alternative approach of the heat load modulation in AC systems there is a concept of incomplete refrigerant evaporation with overfilling air coils that leads to excluding a dry-out of inner surface of air coils and is realized through liquid refrigerant recirculation by injector (jet pump).

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An increase in gas turbine efficiency is possible by inlet air cooling in chillers converting a heat of exhaust gas into refrigeration. In traditional absorption lithium-bromide chillers of a simple cycle an inlet air can be cooled to 15°С. More decrease of turbine inlet air temperature and greater fuel saving accordingly is possible in refrigerant ejector chiller as a simple in design and cheap. The innovative turbine inlet air cooling (TIC) system with absorption chiller as a high-temperature and ejector chiller as a low-temperature stages for cooling air to 7 or 10 °C is proposed. Its application in temperate climate provides annual fuel saving by 1.5 to 2 times higher compared with traditional air cooling in absorption chiller to 15 °C. A novel universal method of analysing the efficiency of TIC system operation and rational designing has been developed. The method involves the simple numerical simulation based on real input data of site actual climatic conditions. The annual fuel saving is chosen as a primary criterion. The novelty of the methodological approach consists in replacing the current yearly changeable fuel reduction due to TIC by its hour-by-hour summation as an annual fuel saving. The increment of annual fuel saving referred to needed refrigeration capacity of TIC system is used as an indicator to select a design refrigeration capacity. A rational design refrigeration capacity determined by applying the novel methodology allows to decrease the TIC system sizes by 10 to 20% compared with traditional designing issuing from the peaked thermal load during a year. So far as it was developed analytically by introducing quite reasonable criterion indicator and based on the simple summation procedure the method is quite applicable for designing in power and energy.