Topic
Variable refrigerant flow
About: Variable refrigerant flow is a research topic. Over the lifetime, 2998 publications have been published within this topic receiving 36496 citations. The topic is also known as: VRF & Variable refrigerant volume.
Papers published on a yearly basis
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Papers
TL;DR: In this paper, the authors reviewed the major research on refrigerant injection techniques in detail and compared them with liquid and vapor refrigerant injections and compared the performance of different types of compressors and variable speed compressors.
Abstract: This paper reviews the major research on refrigerant injection techniques in detail. Liquid and vapor refrigerant injection techniques are discussed and compared. The current research on refrigerant injection techniques falls into two categories: system level research and component level research. The system level research is focused on low ambient temperature heating, heat pump water heating, high ambient temperature cooling, cycle comparison, and control strategy development. Internal heat exchanger and flash tank cycles are the two typical cycles for refrigerant injection. These two cycles are discussed and compared in detail. The component level research is focused on employing different types of compressors, variable speed compressors, the injection process, and the flash tank. Different types of compressors employing refrigerant injection are presented. Based on the literature study, the potential future research directions are presented and discussed. The flash tank cycle control strategy and refrigerant charge management strategy are worth further research efforts. Compressor design can be improved in order to optimize the performance with refrigerant injection. The appropriate design of flash tanks plays a vital role in achieving appropriate two-phase flow patterns in the flash tank. Computational Fluid Dynamics (CFD) modeling can be a useful tool to facilitate the design of the flash tank.
232 citations
Patent•
27 Mar 2003TL;DR: In this article, a refrigerating cycle device using carbon dioxide as a refrigerant capable of solving the problem that when a receiver is installed against a low pressure, a cost and a volume are increased by a pressure resistant design to assure safety.
Abstract: A refrigerating cycle device using carbon dioxide as refrigerant capable of solving such a problem that when a receiver is installed against a low pressure, a cost and a volume are increased by a pressure resistant design to assure safety, wherein a first pressure reducing device (12) and a second pressure reducing device (15) are operated to vary the refrigerant pressure of a first heat exchanger (13) so as to regulate the refrigerant hold amount of the first heat exchanger, whereby since the unbalance of the amount of refrigerant between cooling and heating/dehumidifying can be reduced, the refrigerating cycle device can be efficiently operated with a downsized receiver or without installing the receiver.
198 citations
TL;DR: In this paper, a detailed overview of the configurations of the outdoor and indoor units of a multi-split variable refrigerant flow (VRF) system, and its operations, applications, marketing and cost is provided.
184 citations
Patent•
8 Jul 1988
TL;DR: In this article, a two-wheel hand truck is used to transport a refrigerant recovery system, which includes a compressor having an input coupled through an evaporator and through a solenoid valve to the refrigeration system from which refrigerant is to be withdrawn, and an output coupled through a condenser to a storage container.
Abstract: A refrigerant recovery system which includes a compressor having an input coupled through an evaporator and through a solenoid valve to the refrigeration system from which refrigerant is to be withdrawn, and an output coupled through a condenser to a refrigerant storage container. The evaporator and condenser are contained within a closed cylindrical canister for heat exchange and oil separation, the canister having an oil drain valve in the bottom. The refrigerant storage container is carried by a scale having a limit switch coupled to control electronics to prevent or terminate further refrigerant recovery when the container is full. The entire system, including the control electronics, is mounted on a two-wheel hand truck to facilitate transport to a job site such as a building air conditioning or heat pump system. Apparatus for purifying recovered refrigerant includes a replaceable core filter/dryer, and a liquid pump for circulating refrigerant from the liquid port of the storage container through the core and then to the container vapor port. A differential pressure gauge is connected across the filter/dryer to indicate need for core replacement. A moisture indicator displays water concentration in the refrigerant. The purification apparatus may be either separate from or combined with the recovery system.
160 citations
TL;DR: The fault diagnosis results show that the deep belief network model with initial parameters can be used to diagnose the faults of the variable flow refrigerant system and that the unsupervised restricted Boltzmann machine layer for data feature reconstruction can improve the fault diagnosis performance.
155 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 22 |
| 2020 | 42 |
| 2019 | 34 |
| 2018 | 48 |
| 2017 | 70 |
| 2016 | 85 |