Experimental Confirmation Of Improvement Of Microchannel Condensers By Extraction Circuitry Using R134a

This paper experimentally confirmed the benefits of liquid extraction in microchannel condensers. Experiments are conducted on a mobile air conditioning (MAC) system. R134a is used as the working fluid. An extraction tube with valve is added to one condenser so that it can work in two modes: the conventional mode and the extraction mode. Two types of experiments have been conducted: the heat exchanger-level test and the system-level test. In the heat exchanger-level tests, for the same inlet and outlet enthalpy on the refrigerant side, the extraction mode generates more condensate than the conventional mode. The extraction mode also lowers the refrigerant outlet enthalpy compared to the conventional baseline at the same refrigerant flow rate. The effects of air-side conditions have also been explored. In the system-level test, the air conditioning system with the extraction-mode condenser achieves a higher COP than the baseline under the same superheat and refrigerating cooling capacity

Flow Characteristics in a Microchannel Condensers With Extraction Circuitry

The present study reveals the characteristics of refrigerant flow in a microchannel condenser with the extraction circuitry. The extraction circuitry provides a potential to enhance the condenser performance at almost no cost – the condenser geometry is the same except for a few well-sized drainage holes in the header baffle. A microchannel condenser is modified to run in both the extraction mode and the conventional mode. A 1-D finite-volume model is built for the condenser and is validated with R134a experimental data. The capacities agree within ±5 % and the pressure drops agree within ± 25 %. Using this model, a numerical study is conducted on the condenser. A singleextraction-tube design and a double-extraction-tube design for the extraction mode are both simulated and compared. The flow characteristics in the extraction tube are revealed for a physically possible range of liquid separation efficiency. The effects of flow resistance in the extraction tube on the phase separation efficiency and the condenser performance are also studied

Heat flux transmission assessment of a vegetation wall influence on the building envelope thermal conductivity in Belgrade climate

Vegetation integration in architectural buildings is one of the sustainable approaches for the building's facade development. The vegetation walls in architecture are innovative concepts of green building. This paper deals with the experimental and theoretical examination of vertically greened walls in the process of facade envelope optimization. The objective is to determine the contribution of the vegetation walls to the improvement of the energy properties of the envelope through experiments and models. The research analyzed the energy specificity of the vegetation walls and their contribution to the improvement of the thermal properties of the facade coating in Belgrade climatic conditions. For the research purposes, an experimental model was developed on which the relevant temperature values and thermal conductivity coefficients were measured. Measurements have shown that vegetation affects the reduction of the surface temperature of the envelope and affects the value of the thermal conductivity coefficient of the facade envelope. The research has shown that the facade wall containing plants has a significant influence on the temperature balance in the facade of the building. The methodology presented in this paper is based on the analysis of the climate characteristics in the measuring area, measurement of temperature values in the experimental model and comparative analysis. During the experiment, the vegetation elements were treated as elements that influence the facade envelope overheating reduction. It has been concluded, from previous researches, that by using the vegetation walls, the south-oriented wall has a lower thermal absorption and a lesser value of heat flux. Data analysis enabled the assessment of the thermal insulation efficiency of the wall using vegetation during the summer period. The proposed methodology enables a quantitative analysis of the effects of vertical greenery

Can carbohydrates change the shape of water?

Aquaphotomics is a relatively novel scientific discipline which can be used for elucidation of structural and related functional properties of aqueous systems. The aim of this study was to analyse water solutions of carbohydrates of different size from monosaccharides (glucose and fructose) via, disaccharides (sucrose), gluco and fructo-oligosaccharides and various selected polisaccharides (based on glucose and fructose, respectively) using Aquaphotomics. Knowing that main functions of carbohydrates within our body are various: providing energy and regulation of blood glucose; sparing the use of proteins for energy; breakdown of fatty acids and preventing ketosis; biological recognition processes; flavor and sweeteners and dietary fibers who can promote digestive health, knowledge about their interaction with water molecules can have strong influence on our understanding of some basic but also complex metabolic processes

Can carbohydrates change the shape of water?

Aquaphotomics is a relatively novel scientific discipline which can be used for elucidation of structural and related functional properties of aqueous systems. The aim of this study was to analyse water solutions of carbohydrates of different size from monosaccharides (glucose and fructose) via, disaccharides (sucrose), gluco and fructo-oligosaccharides and various selected polisaccharides (based on glucose and fructose, respectively) using Aquaphotomics. Knowing that main functions of carbohydrates within our body are various: providing energy and regulation of blood glucose; sparing the use of proteins for energy; breakdown of fatty acids and preventing ketosis; biological recognition processes; flavor and sweeteners and dietary fibers who can promote digestive health, knowledge about their interaction with water molecules can have strong influence on our understanding of some basic but also complex metabolic processes