Analysis Of The Coefficien Of Performance (COP) Freezer Produced By Solar Cell

The use of freezer machines has now become a necessity for the wider community, because it is very helpful for humans in everyday life. The cooling load given greatly affects the performance of the freezer, both in terms of electrical energy consumption and the ability to increase system usage time. The greater the cooling load will increase the use of electrical energy during operation. This is very worrying in the future where the issue of depleting fossil energy sources which is currently a priority for producing electrical energy is increasing and filling the media. In recent years, solar energy has been rumored to be the answer to this problem. Where heat energy from the sun is used to move protons and electrons in a solar panel media to produce electrical energy that can be used for the needs of many people. This has become the attraction of researchers to make an innovation in the use of solar energy in a freezer system. Judging from the research roadmap related to solar energy and the vapor compression system in the freezer that was launched in the last few years, not many innovations have been carried out in the use of energy sources. The cooling load to be used will be adjusted to the capacity of the energy source used, which is 410 WP. With the capacity of the freezer that is used with a power of 1/4 PK which will increase its ability/ efficiency to be used and replace the paid electric energy freezer. This is expected to be useful for the public and contribute knowledge and help realize the university roadmap in the future.

Analysis of supplemental dehumidification for increased energy efficiency of shoulder seasons based on climate change predictions in Austin Texas

This research project compared a standard vapor compression system and a standard desiccant dehumidification system with heat wheel to determine if there was some potential energy savings for “shoulder season” hours in Austin Texas. “Shoulder season” hours as defined in the paper are hours during which the dry bulb temperature falls within the American Society of Heating Refrigeration and Air Conditioning Engineers (ASHRAE) comfort bound but the humidity is above the comfortable humidity point. These hours are normally addressed with vapor compression systems which dehumidify by cooling the air under the comfort setpoint to dehumidify, which is wasteful of energy. The study found that for these shoulder season hours a desiccant dehumidification system was around 4.5 times more energy efficient at reaching comfort setpoints if free heating was used for drying the desiccant.

An Experimental Investigation on Vapor Compression Refrigeration System Cascaded with Ejector Refrigeration System

A conventional vapor compression refrigeration system (VCRS) cascaded with a heat-assisted ejector refrigeration system (ERS) has been experimentally analyzed. Cascading allows the VCRS to operate at lower condenser temperatures and thus achieve a higher coefficient of performance. In this cascaded system, the condenser of the vapor compression system does not dissipate its heat directly to the evaporator of the ERS; instead, water circulates between the condenser of VCRS and the evaporator of ERS to exchange the heat. Seven ejectors of different geometries have been used in the ERS; however, all the ejectors could not maintain thermal equilibrium at the desired operating conditions. The compressor of the cascaded VCRS consumed 1.3 times less power than the noncascaded VCRS. Furthermore, the cascaded system provided a maximum 87.74% improvement in COP over the noncascaded system for the same operating conditions. The performance of the system remained constant until the critical condenser pressure of the ERS.

Transient State Modelling and Experimental Investigation of the Thermal Behavior of a Vapor Compression System

The main objective of this work is to establish a detailed modelling technique to predict the refrigerant conditions such as pressure and enthalpy of a VC system. The transient state modelling techniques suggested in many research works are usually not easy to reproduce due to lack of detailed methodology and the multitude of analytical or computational schemes that could not be assessed objectively. This work has addressed this issue by introducing a modelling method developed from conservation equations of mass and energy represented with Navier–Stokes equations. A finite volume scheme has been used to discretize the governing equations along the heat exchanger models. Transient state modelling matrices have been established after dividing the condenser as well as the evaporator into 3 and n control volumes. The model validation with experiments was satisfactory. The model outputs such as the refrigerant pressure across the condenser and evaporator are in agreement with experiments. The proposed modelling technique could be adopted to predict optimal parameters during start-up. The modelling results could be used to design VC systems with optimal performance.

Experimental and simulation study of the performance of a desiccant loop cooling system

The paper presents experimental data and results from a prediction tool for the performance of a desiccant loop cooling system. The experiments are performed under a variety of high humidity and hot ambient conditions and the system performance is described. One of the experimental conditions is typical of many Indian cities and the systems appropriate for those cities are established. A simulation program that can predict the performance of the desiccant loop is developed. The simulation results show that this system can work as effectively as vapor compression air-conditioning for certain ambient conditions whereas it can function as a pre-cooler to a vapor compression system under more severe conditions, resulting in a reduced power consumption. The results presented in the paper give a guideline to practicing engineers as to when a desiccant loop cooling system would be useful. A simple payback analysis and a lifecycle cost analysis shows that a desiccant cooling system with a waste heat recovery recuperator is an economically viable investment.

Nanofluid as Advanced Cooling Technology. Success Stories

Nanofluids are defined as heat transfer fluids with enhanced heat transfer properties by the addition of nanoparticles. Nanofluid’s stability, nanoparticles’ type and their chemical compatibility with the base fluid are essential not only to increase the nanofluid’s thermophysical properties but also to ensure a long-lasting and thermal efficient use of the equipment in which it is used. Some of these aspects are discussed in this chapter. Likewise, the improvement in terms of the heat transfer capacity (thermal resistance) that the use of nanofluids has on the heat pipes-thermosyphons is shown. On the other hand, the improvement in energy efficiency that nanofluid causes in a vapor compression system is also presented.