New Regenerative Cycle for Vapor Compression Refrigeration

Abstract

Project Objective (as stated in the proposal): The main objective of this project is to confirm on a well-instrumented prototype the theoretically derived claims of higher efficiency and coefficient of performance for geothermal heat pumps based on a new regenerative thermodynamic cycle as comparing to existing technology. In order to demonstrate the improved performance of the prototype, it will be compared to published parameters of commercially available geothermal heat pumps manufactured by US and foreign companies. Other objectives are to optimize the design parameters and to determine the economic viability of the new technology.Background (as stated in the proposal): The proposed technology closely relates to EERE mission by improving energy efficiency, bringing clean, reliable and affordable heating and cooling to the residential and commercial buildings and reducing greenhouse gases emission. It can provide the same amount of heating and cooling with considerably less use of electrical energy and consequently has a potential of reducing our nations' dependence on foreign oil. The theoretical basis for the proposed thermodynamic cycle was previously developed and was originally called a "dynamic equilibrium" method. This theory considers the dynamic equations of state of the working fluid and proposes the methods for modification of T-S trajectories of adiabatic transformation by changing dynamic properties of gas, such as flow rate, speed and acceleration.The substance of this proposal is a thermodynamic cycle characterized by the regenerative use of the potential energy of two-phase flow expansion, which in traditional systems is lost in expansion valves. The essential new features of the process are:1. The application of two-step throttling of the working fluid and two-step compression of its vapor phase. 2. Use of a compressor as the initial step compression and a jet device as a second step, where throttling and compression are combined 3. Controlled ratio of a working fluid at the first and second step of compression.

Energy and exergy efficiencies of different configurations of the ejector-based co2 refrigeration systems

“…This innovative cycle was recently introduced by Bergander [9]. In this cycle, ejector is used as a second-stage compressor.…”

Strategies to recover and minimize boil-off losses during liquid hydrogen storage

“…Ejectors have a wide range of applications, including as jet pumps or compressors [92]. They are used to support vacuum operations [96] as well as for transfer and mixing pumps [97,98]. The use of ejectors can reduce throttling losses and increase the suction pressure of refrigeration systems, thereby reducing the compression work required for the process [99].…”

Progress and challenges in utilization of ejectors for cryogenic cooling

“…Ejectors, also referred to as jet pumps or compressors, can be used to support vacuum operations [1], or they can be operated as transfer and mixing pumps [2][3][4]. Ejectors are fascinating devices, which have an interesting history.…”