First day 25 november 2018 – oryx chapter gas in back trapped


The work deals with the prediction of the hydrodynamic and thermal fields on the airflow side of an AC unit. The flow in the evaporator compartment is modeled as a two-phase flow (gas and liquid) with the gas phase composed of two species (dry air and water vapor). In the condenser section however, the flow is treated as a single-phase flow. Predicted sensible and latent cooling capacities for several design conditions are in close agreement with available experimental data. electricity games online free The differences between the total capacities computed by the model in the evaporator section and those reported experimentally are within 2.7% for all cases considered. mp electricity bill payment Predictions in the condenser section resulted in a load that is only 0.00136% different from the one calculated using experimental data. To improve the performance of the unit, six different modified designs of the evaporator coil are developed and tested. One of the designs resulted in 6.18% decrease in the cooling capacity, while the remaining modifications increased the cooling capacity by values ranging between 2.17% and 8.6%.

HFC have been selected as alternative refrigerants in phasing out ODSs as per Montreal Protocol. The Kigali Amendment was adopted on October 15, 2016, in Kigali, Rwanda. The amendment acknowledged the importance of energy efficiency when transitioning HCFC/HFC to low-GWP technologies. electricity grid uk Developed countries will begin reducing high GWP HFCs as early as 2019. Developing countries began their HCFC phase-out with a freeze in 2013 and a 10% reduction in 2015 and will make further reductions to 35% in 2020, 67.5 in 2025, 97.5% in 2030 and 100% in 2040. This phase-out schedule for developing countries offers the opportunity to leapfrog directly to low-GWP alternative refrigerants. This presentation will highlight the Kigali amendment and explain what it takes for countries to be prepared to start implementing the amendment. Energy efficiency and setting safety standards relevant to low global-warming-potential alternatives are essentials while implementing the amendment. The presentation will address the importance of MEPS, as well as, twinning the efforts and collaboration between refrigerant experts and the energy efficiency practitioners.

In Qatar and surrounding areas there is an opportunity to design and construct buildings which use ‘passive solar’ solutions which can achieve satisfactory thermal comfort using the building construction itself to act as the first level of cooling using ‘solid’ thermal mass which can absorb heat, shading which can prevent solar gains reaching a building and natural ventilation for free air cooling whenever outside air temperatures are below interior temperatures.

Whenever necessary mechanical cooling systems will be needed to deal with higher gains during very hot weather. However even these systems should take opportunities such as night cooling to provide coolth economically at low carbon energy levels. electricity worksheets high school Night cooling can meet the following daytime needs if coolth is stored in water circuits with phase change materials inside storage tanks. There is also an approach which pre-cools a buildings fabric itself during night time so that it is ready for use a cool structure next day. kite electricity generation The guide shows how these can be combined to provide resilience and performance.

Designs should combine passive with mechanical cooling to achieve optimum solutions. For example, it would be possible to naturally ventilate buildings in Qatar in the 6 months autumn – winter – spring period and to add mechanical cooling during the 6-month spring – summer – autumn period. This hybrid approach is very cost effective because it saves around 50% cooling over a year.

ASHRAE provides weather data for future years taking account of predicted climate change. The guide explains how these weather files can be used to ensure that buildings are sufficiently robust to cope with future weather conditions and are fit for purpose during hot periods. The guide will cover the range of analysis methods available to designers who want to predict summertime conditions and use the results to size and select equipment.