HFCs (Hydrofluorocarbons) are one of the most widely used refrigerants worldwide. But, HFCs are heading towards complete phase out in the near future due to environmental concerns. A high global warming potential (GWP) of HFCs is the main reason for its phase-out. As a result, researchers, engineers and technicians associated with the refrigeration sector are looking for a suitable environment-friendly alternative. Recent past has witnessed the emergence of a new group of environment-friendly refrigerants known as the HFOs (Hydrofluoro-olefins). The present review is focussed on addressing various aspects of HFO refrigerants such as the thermodynamic and transport properties, flammability and oil compatibility, boiling and condensation heat transfer performance and their performance in actual vapour compression refrigeration systems. Few suggestions for future research work related to HFO refrigerants are also discussed.

HFO refrigerants: A review of present status and future prospects.

Survey of Data and Models for Refrigerant Mixtures Containing Halogenated Olefins

In this work, a feed-forward artificial neural network (ANN) was developed for the calculation of isobaric heat capacity of pure HFC and HFO refrigerants in liquid phase. First of all, a total of 1142 available experimental data points for different pure HFC or HFO refrigerants were collected and evaluated before being used to train and test the network. By a trial-and-error method, optimum structural of the network was found out to be an input layer using four dimensionless input parameters, one hidden layer with 34 neurons, and an output layer with reduced residual heat capacity as output. The ANN was applied for 12 different refrigerants, and the predicted isobaric heat capacity showed satisfactory agreement with experimental data. The overall average absolute deviation (AAD %) and maximum absolute deviation (MAD %) were 0.383% and 5.92% respectively.

An artificial neural network for the residual isobaric heat capacity of liquid HFC and HFO refrigerants

A simple generalized equation for compressed liquid isochoric heat capacity of pure and mixture refrigerants

Modeling heat capacity of saturated hydrocarbon in liquid phase over a wide range of temperature and pressure

In order to get the internal parameters of a vortex tube, a large-scale vortex tube was designed and an experimental device was built. A five-hole probe and thermocouples were used to obtain the three-dimensional velocities, the static pressure, static temperature and total temperature distributions inside the vortex tube. Four different cold mass fraction conditions (0.2, 0.4, 0.6 and 0.8) were chosen and the impacts on the internal parameters of the vortex tube were discussed. Different from the traditional view, the tangential velocity was considered to be the steady Burgers vortex form. A reverse flow boundary was found, and the location of which was changed at different operation conditions and axial positions. Further, it was found that the lowest static temperature existed near the nozzle outlet, and a new static temperature difference distribution law was firstly proposed experimentally.

Experimental study of the impacts of cold mass fraction on internal parameters of a vortex tube

A corresponding state equation for the prediction of isobaric heat capacity of liquid HFC and HFO refrigerants

In this work, isobaric heat capacity of liquid refrigerants mixtures was investigated experimentally and theoretically. First of all, experimental isobaric heat capacity data of a representative HFC-32+HFO-1234ze(E) binary mixture was obtained by a modified Calvet calorimeter at different temperatures and concentrations. After that, a previously proposed corresponding state equation, which was used for estimation of isobaric heat capacity of pure liquid HFCs and HFOs refrigerants, was extended to mixtures. Different mixing rules for pseudo-critical parameters were tested and a comparison between predicted values and experimental data was carried out in search of a best mixing rule. In the end, the corresponding state equation coupled with the selected mixing rule was applied to other binary mixtures R-410A, R-507A and ternary mixtures R-404A, R-407C. It was found that the calculated results agreed well with their fundamental Helmholtz equations of state. The average absolute deviation was 0.88% and maximum absolute deviations were no more than 1.90%.

Experimental isobaric heat capacity of liquid HFC-32+HFO-1234ze(E) mixture and extension of a predictive corresponding state equation to HFC mixtures

The invention discloses a portable cold-hot dual-purpose electric fan based on vortex tubes. The electric fan comprises a fan, a gas compression device, an electric motor used for driving the fan andthe gas compression device, and a vortex tube device connected with the gas compression device, wherein the gas compression device generates high-pressure gas under the driving of the electric motor and the high-pressure gas enters the vortex tube device; and the vortex tube device converts the high-pressure gas into a cold gas flow and a hot gas flow, and the fan drives and diffuses the cold gasflow to a space requiring cooling or drives and diffuses the hot gas flow to a space requiring heating. The electric fan can simultaneously generate cold air and hot air, and has the characteristics of being simple in structure and convenient to carry.

Portable cold-hot dual-purpose electric fan based on vortex tubes

The invention discloses a refrigeration and heating device based on a vortex tube. The refrigeration and heating device based on the vortex tube is characterized by comprising a drive device, a gas compression device and a vortex tube device, wherein the drive device drives the gas compression device to generate high-pressure gas and enabling the high-pressure gas to enter into the vortex tube device; the vortex tube device converts the high-pressure gas to cold gas flow and hot gas flow; and the drive device is a hand rocker or a fan blade. The refrigeration and heating device does not dependon energy supply of an environment, and refrigeration and heating effects can be generated in a tent only by manual mechanical drive or by virtue of wind energy; and the refrigeration and heating device has the characteristics of being simple in structure, convenient to carry, and the like, and suitable for being applied to camping in the wild without power supply provision and abundant wind power resources.

Liming Tang

Papers

Experimental study of the impacts of cold mass fraction on internal parameters of a vortex tube

A corresponding state equation for the prediction of isobaric heat capacity of liquid HFC and HFO refrigerants

Experimental isobaric heat capacity of liquid HFC-32+HFO-1234ze(E) mixture and extension of a predictive corresponding state equation to HFC mixtures

Portable cold-hot dual-purpose electric fan based on vortex tubes

Refrigeration and heating device based on vortex tube