Research on drying Lentinus edodes in a direct expansion heat pump assisted solar drying system and performance of different operating modes

Considering the problems of high energy consumption, complex system structure and low drying temperature in current industrial drying system of metal parts, a closed loop heat pump drying system with auxiliary condenser was designed and established. The effects of auxiliary condenser operation parameters on the circulating air temperature, coefficient of performance (COP), moisture extraction rate (MER) and specific moisture extraction rate (SMER) were experimentally investigated, where the compressor rotating speed, circulating air volume, cooling water inlet temperature and flow rate respectively were 3900 r•min−1, 539.8 m3•h−1, 5∼30 °C and 30.6∼50.1 kg•h−1. The results showed that the drying temperature gradually increased with increasing cooling water inlet temperature and decreasing cooling water flow rate. When the cooling water inlet temperature and flow rate respectively were 20 °C and 34.3 kg•h−1, the drying temperature was 70.02 °C, meeting the high temperature requirement of industrial drying. Besides, the cooling water flow rate had little influence on the system COP, while the system COP increased at first and then decreased with increasing cooling water inlet temperature, reaching its maximum value 5.64 when the cooling water inlet temperature was 20 °C. Moreover, when the cooling water inlet temperatures respectively were 20 °C and 5 °C with constant cooling water flow rate 34.3 kg•h−1, the system MER and SMER could reach their maximum values of 3.8 kg•h−1 and 1.68 kg•kW−1•h−1, showing excellent dehumidification capacity. These results can provide guidance for the popularization and application of heat pump drying technology in the industrial drying. 

Study on the effects of auxiliary condenser operation parameters on the performance of closed loop heat pump drying system

• A novel open-loop air cycle heat pump drying system is proposed. • The mathematical model built is verified to be both accurate and feasible. • Compared with electric heating drying system, the energy-saving rate of air cycle heat pump water heater system is 15∼27%. • The impact of different working conditions on system performance was determined. Different from conventional drying technology, the novel technology of an air cycle heat pump drying (ACHPD) system, using air as its working medium, is proposed to solve the problems of low energy efficiency, HCFC refrigerant use, and so on. A mathematical simulation model is constructed to evaluate system performance under various working conditions, and its verification via experimental results from a constructed test bench produced errors of temperature within ±1.6%, of drying rate within ±0.01%, and of system power within ±7%. Compared with a conventional electric heater drying (EHD) system, the energy-saving rate of the ACHPD system reaches about 15–27% when the mass evaporation rate increases from 0.75 kg h −1 to 3.45 kg h −1 . Under set working conditions, an increase of inlet air flow rate (150–400 kg h −1 ) improved the dehumidification energy efficiency ratio (MER) by about 1%. However, the increase of inlet air temperature (10–40 °C) and relative humidity (30–80%) reduced MER by about 7% and 21% respectively. The efficiency improvements of heat exchanger (0.3–0.8) can improve the energy efficiency of system by 20%; however, the efficiency improvements of expander (0.55–0.8) and compressor (0.4–0.9) can deteriorate the energy efficiency of system by 17% and 36% respectively. These results would provide new technical references for the application of heat pump technology in drying field from a different perspective. 

Simulation Investigation on a Novel Open-loop Air cycle Heat Pump Drying System

Operating characteristics of sludge heat pump dryer and influencing factors of performance: a field experiment in an electroplating factory

Study on the effect of circulating air volume on the performance of closed loop heat pump drying system

Effect of compressor speeds on performance of a closed loop heat pump drying system

The invention provides a vacuum evaporation type beverage quick-cooling device. The vacuum evaporation type beverage quick-cooling device comprises a cup body, a cooling water circulation loop and a PLC. The cup body comprises a cooling cavity and an evaporation cavity. The evaporation cavity wraps the cooling cavity. Beverages are stored in the cooling cavity. The cooling water circulation loop comprises a water inlet pipe, a vacuum pump, a water collecting container, an evaporation module and a water return pipe. The water inlet pipe is connected with the evaporation cavity and is provided with a water supplement valve. The vacuum pump communicates with the water collecting container through a first gas pipe. The water collecting container communicates with the top end of the evaporationcavity through a second gas pipe. The evaporation module is arranged in the water collecting container. The bottom of the water collecting container communicates with the evaporation cavity through the water return pipe. A water return valve is arranged on the water return pipe. The PLC is electrically connected with the vacuum pump and the evaporation module respectively. The vacuum evaporationtype beverage quick-cooling device fully utilizes the characteristics of a relative large amount of vaporization latent heat of water to realize quick cooling, and is small in occupied space, low in device cost and high in energy utilization rate; and PLC control is adopted, one key can be used to realize control after the beverages are injected, and the operation is convenient and quick.

Vacuum evaporation type beverage quick-cooling device

The invention puts forward a quick cooling device used for a beverage. The quick cooling device comprises a cup body and a cup lid, wherein the cup body comprises a cup liner and a cup shell; the cupliner is arranged in the cup shell; a gap between the cup shell and the side wall of the cup liner is a circulation air duct; a gap between the cup shell and the bottom of the cup liner is an inlet air duct; the circulation air duct is filled with ventilation materials; the side wall of the bottom end of the cup shell is provided with an air inlet; the air inlet just faces the inlet air duct; thecup lid comprises an inner lid and an outer lid, wherein the inner lid and the opening of the cup liner are cooperatively connected; the outer lid and the opening of the cup shell are cooperatively connected; a gap between the outer lid and the inner lid is an outlet air duct; the outer lid is provided with a fan; and the fan just faces the outlet air duct. In the quick cooling device, single-direction circulating wind made by the fan is used for penetrating through and taking away heat transferred by the ventilation materials to lower the temperature of the beverage in the cup liner so as tobe convenient to drink. The whole device has a low cost, occupies a small space, has a light weight, is efficient to use and is convenient to carry.

Li Zhenbo

Papers

Effect of compressor speeds on performance of a closed loop heat pump drying system

Vacuum evaporation type beverage quick-cooling device

Quick cooling device used for beverage