Experimental investigation of using Graphene Oxide with Ethylene Glycol and Water mixture to improve the performance of a car radiator

Nanofluids offer a good alternative heat transfer mediums with approximately five-fold heat transfer enhancement. This paper presents the results from a research study carried out on the use of Graphene Oxide/ Ethylene glycol Mixture (GnO/H2O-EG) Nanofluid as the heat transfer medium in a car radiator. The radiator consisted of 30 vertical tubes with elliptical cross section. Air makes a cross flow inside the tube bank with constant speed. The system was tested with three different Nanofluid concentrations (0.1, 0.3 and 0.5% by weight). The tests were conducted for flow rates ranging between 2 to 5 lit/min which corresponds to Reynolds number between 14000 and 38000. The effect on fluid outlet temperature to the radiator was analyzed for different flow rates and constant inlet temperature. The data were compared to that obtained with potable water in the radiator. The result of the comparison revealed that the use of graphene oxide increased the temperature drop across can radiator by upto 22 % compared to 50% Glycol mixture

Trigeneration in food retail: An energetic, economic and environmental evaluation for a supermarket application; Applied Thermal Engineering

This paper presents results on the evaluation of energy utilisation efficiency and economic and environmental performance of a micro-gas turbine (MGT) based trigeneration system for supermarket applications. A spreadsheet energy model has been developed for the analysis of trigeneration systems and a 2800 m2 sales area supermarket was selected for the feasibility study. Historical energy demand data were used for the analysis, which considered factors such as the fraction of the heat output used to drive the absorption chillers, the chiller COP and the difference between electricity and gas prices. The results showed that energy and environmental benefits can be obtained from the application of trigeneration systems to supermarkets compared to conventional systems. The payback period of natural gas driven trigeneration systems and greenhouse gas emissions savings will depend on the relative gas and electricity prices and the COP of the vapour compression and absorption systems. It was also shown that operation at full electrical output gives a better performance than a heat load-following strategy due to the reduction of the electrical generation efficiency of the MGT unit at part load conditions