Condition Of Heat Pump Research Articles

Justification of the power of the heat pump used in the cooling system of the steam turbine condenser of the CCGT-CHP

THE PURPOSE. Determination of the permissible power of the heat pump (HP) used in the cooling system of the steam turbine condenser for a thermal power plant (TPP) based on double-circuit combined-cycle gas turbine (CCGT).METHODS. Mathematical modeling of the operating modes of a heating CCGT with a HP in the cooling system was used as a research method. The research was conducted using statistical data on technical parameters and economic indicators of CCGT-450, for climatic and market conditions of St. Petersburg. The research of the most characteristic modes of operation of the main power equipment, in the annual context, was carried out. The maximum permissible capacity of the HP, from the point of view of the organization of stable heat supply to the consumer, available low-potential resources and breakeven operation of TPP in the electricity market was determined.RESULTS. It was found that lowpotential energy resources in the cooling system of the steam turbine condenser are formed in significant volumes and the thermal power of the consumer is consistently high, including in summer. Therefore, market restrictions related to the break-even operation of TPP in the wholesale electricity market are the most essential condition determining the permissible level of HP power. It was found that for the object of study, with an average annual electrical capacity of 650 MW, the maximum power of the HP is 160 MW.CONCLUSION. The main factors limiting the permissible level of HP power were analyzed using the example of a real power facility. A direct connection between the maximum capacity of the HP and external economic conditions, as well as the level of energy efficiency of the TPP equipment was established. This approach can be used to select and justify the HP capacity regardless of the location region, the type of power system, the cost of energy resources, market conditions, as well as the type and characteristics of the equipment used.

Machine learning and in silico discovery of metal-organic frameworks: Methanol as a working fluid in adsorption-driven heat pumps and chillers

With the increasingly serious energy-consumption, the adsorption-driven heat pumps/chillers were paid more attention. To select the promising adsorbents and suitable working fluids in this technology, a high-throughput computational screening of 6013 computation-ready experimental metal organic frameworks (MOFs) is employed to identity the best candidates for methanol-MOF pairs in adsorption-driven heat pumps and chillers. The highest working capacity (ΔW) and coefficient of performance (COP) under operating condition of heat pump are 512.86 mg/g and 1.83, respectively. The structure-performance relationships are derived for ΔW and COP with 6 MOF descriptors, the saturated ΔW is, for the first time, defined for the improvement of heat pump efficiency, and 10 best MOFs are identified. Then four machine learning algorithms are applied to predict the relative importance of each MOF descriptor. The microscopic insights obtained from our bottom-up approach provide the guidelines for the design of new MOFs in adsorption-driven heat pumps and chillers.

Experimental Evaluation on Low Global Warming Potential HFO-1336mzz-Z as an Alternative to HCFC-123 and HFC-245fa

HFO-1336mzz-Z with low global warming potential (GWP) was considered as a promising alternative of HCFC-123, HFC-245fa in air conditioning (AC) and heat pump (HP), respectively. In order to understand the operation performances of HFO-1336mzz-Z and HCFC-123, HFC-245fa in different working conditions, an experimental setup for testing the refrigeration cycle performance was built. The cycle performances of HFO-1336mzz-Z and HCFC-123 in AC conditions, HFO-1336mzz-Z and HFC-245fa in HP conditions were investigated by experiment. It was found in AC conditions, the discharge temperatures for the systems with HFO-1336mzz-Z and HCFC-123 were lower than 115 °C, the cooling capacity of the system with HFO-1336mzz-Z was 27% less than that with HCFC-123 at least, and the coefficient of performance (COP) of the system with HFO-1336mzz-Z was 0.1 lower than that with HCFC-123; in HP conditions, the discharge temperature with HFO-1336mzz-Z was lower than that with HFC-245fa, the former was never over 115 °C while the latter was up to 126 °C, the power input to the compressor with HFO-1336mzz-Z was 20% less than that with HFC-245fa in the same HP conditions, the heating capacity of the system with HFO-1336mzz-Z was 30–40% less than that with HFC-245fa.

96/05459 Performance of a scroll compressor with R134a at medium temperature heat pump conditions

A modern refrigeration process requires constant control to provide required cooling for the user. To properly and economically accommodate this need, a wide operation range of the compressor is necessary. Therefore, it is of interest to investigate the off-design operation of a cooling cycle and compressor. The refrigeration cycle equipped with a two-stage centrifugal compressor and a flash intercooler is studied. The compressor operation maps are generated with two different design codes and the operation values of the compressors are interpolated from the compressor maps in the simulation of the entire cooling cycle. Based on the previous studies of the utilised refrigeration cycle, R245fa is selected as coolant. The aim of this study is to demonstrate the control capacity of the centrifugal compressor and the performance of the cooling loop in off-design conditions. This configuration provides better and wider control over the cooling range than the traditional on-off control of displacement compressors.

Performance of a scroll compressor with R134a at medium temperature heat pump conditions

The isentropic and volumetric efficiency of a scroll hermetic compressor is measured using R134a under medium temperature heat pump conditions. The evaporating temperature ranges from 3 to 36°C and the condensing temperature from 34 to 78°C. The efficiency parameters are fitted to functions of the suction and discharge pressures. At the same port pressures, there are only small differences between the isentropic and volumetric efficiency parameters for R134a and those for R22, the latter determined from the manufacturer's data. The efficiency parameters for R134a are used to compare the performance of the compressor with R12, R134a and R152a in a medium temperature heat pump cycle. The COP and heating capacity exhibit trends similar to those in previous experimental data for a reciprocating compressor.

The HallScrew compressor for refrigeration and heat pump duties

The construction of the HallScrew compressor, based on the Zimmern single-screw invention, is described and its basic advantages are outlined. A computer model of the basic geometry is used to explore the advantages of changes in the propertions of the machine, including the numbers of flutes and teeth on the rotors. Performance is reported for a range of standard machines operating on R 22 and R 717 including the effects of unloading, liquid injection and economiser operation. Some data are given for heat pump conditions using R 114.