The importance of industrial heat pumps for decarbonization has gained widespread recognition. In particular, research, development and demonstration of high-temperature heat pumps with supply of 100°C or higher are being accelerated especially in Europe. This paper reviews these technological trends and identifies issues for future research and development in Japan. Specifically, the report extracts the following future activities: the development of lubricant oil suitable for high temperature conditions, research on the construction of a compact and inexpensive steam supply system with high efficiency and controllability, and the development of technologies and standards to expand the application of natural refrigerants, including those with strong combustion properties.

Renewable energies are increasingly being used in order to achieve Carbon Neutrality. Energy supply and demand adjustment is getting more and more important recently. Predicting energy consumptions of each equipment is important for efficient operational management. In particular, air-conditioning equipment (HVAC) accounts for a large proportion of power consumption. This paper reports on the results of developing machine-learning based models to solve the problem of estimating the hourly power consumption of office HVAC equipment in office buildings.

Current thermal management technology for electric vehicles is investigated and issues identified. One key issue is the consumption of electrical energy due to battery cooling, anti-fogging of the windshield by introducing outside air and cabin heating. Another issue is cabin heating being interrupted during the defrosting operation of heat pump. Solutions are proposed as follows:

・Batteries to be cooled using the evaporation latent heat of the condensate water as a by-product of cabin cooling.

・A desiccant-coated heat exchanger is adopted to dehumidify the inside air of the cabin. Accordingly, this facilitates anti-fogging of the windshield by recirculating the interior air , allowing less fresh air into the vehicle cabin and less resulting heat loss due to incoming cold fresh air.

・Furthermore, to maximize the electrical energy savings, heat generated by motors and invertors is recovered as a supplemental heat source of the heat pump.

・The heat generated by batteries is utilized to remove the frost on the evaporator surface of the heat pumps, whereupon the cabin can be heated continuously.

This system can be operated in three modes: cooling mode for the cabin, battery, motor and invertor, heating mode for the cabin and battery, defrosting and cabin-heating mode. A system description of the three modes is given in this paper and the system performance during defrosting and cabin-heating mode is analyzed in detail. According to cycle simulations, based on a weight of 294 kg and heat recovery from the battery stored at 25°C, 162g of defrosting can be achieved within five minutes while heating the cabin. The decrease in battery temperature in this case is approximately 4°C and the compressor's power consumption is below 1 kW.

Saving energy in the heating is one of the important issues for the widespread use of electric vehicles (EVs). In this report, the performance of the heating operation mode was investigated included in the thermal management system proposed in the previous report. This system is constructed from the vapor compression heat pump and a desiccant-coated heat exchanger (DCHE). It aims to save energy in anti-fog operation by a reduction in outdoor air intake, which is a cause of increased heating load. A performance test of DCHE was conducted, and it was revealed that anti-fogging performance was improved by appropriate adsorption heat removal and adsorption temperature control. System performance was predicted using the experimental results. The power consumption was reduced by 73.4% compared to an electric heater and 37.6% compared to a conventional heat pump system.