The use of high temperature heat pumps (HTHPs) operating with natural fluids has been
shown to be a potential environmentally friendly solution to increase energy efficiency in …

Carbon dioxide is a safe, economic and environmentally sustainable refrigerant which can
be used in heat pump and refrigeration systems. Research into the performance and …

This paper presents the results of an experimental study of the flow visualization of the
refrigerant R600a through a capillary tube with an internal diameter of 0.8 mm made from a …

A capillary tube based CO2 heat pump is unique because of the transcritical nature of the
system. The transcritical cycle has two independent parameters, pressure and temperature …

Experimental studies for a prototype CO2 heat pump system employing capillary tube as an
expansion device for simultaneous water heating and cooling have been presented. Tests …

Flow of CO 2 in the vicinity of its critical point was studied experimentally in two different flow
configurations. First, a 60 cm long stainless steel pipe with 2.1 mm inner diameter was used …

In this work, a thermodynamic model based on a small CO 2 water-source heat pump water
heater is proposed and discussed. The usefulness of the model lies in the possibility of …

In this study, a transcritical CO 2 heat pump system using a capillary tube as an expansion
device was experimentally investigated. A prototype was developed for this purpose …

Two expansion devices designed for CO 2 refrigeration systems namely, capillary tube and
fixed-geometry ejector were experimentally tested in the SINTEF/NTNU laboratory in …

A separated flow model of coiled adiabatic capillary tube for CO2 considering metastable
flow region is presented. In the case of straight capillary, different friction factors are …