scholarly journals Year-round Flowering of Phalaenopsis under Spot Cooling System Using Spot Air-conditioner.

1997 ◽  
Vol 9 (3) ◽  
pp. 193-198
Author(s):  
Hiroaki HIRAI ◽  
Genjiro MORI
Author(s):  
Pramit Ghosh ◽  
Debotosh Bhattacharjee ◽  
Mita Nasipuri ◽  
Dipak Kumar Basu

Low cost solutions for the development of intelligent bio-medical devices that not only assist people to live in a better way but also assist physicians for better diagnosis are presented in this chapter. Two such devices are discussed here, which are helpful for prevention and diagnosis of diseases. Statistical analysis reveals that cold and fever are the main culprits for the loss of man-hours throughout the world, and early pathological investigation can reduce the vulnerability of disease and the sick period. To reduce this cold and fever problem a household cooling system controller, which is adaptive and intelligent in nature, is designed. It is able to control the speed of a household cooling fan or an air conditioner based on the real time data, namely room temperature, humidity, and time for which system is active, which are collected from environment. To control the speed in an adaptive and intelligent manner, an associative memory neural network (Kramer) has been used. This embedded system is able to learn from training set; i.e., the user can teach the system about his/her feelings through training data sets. When the system starts up, it allows the fan to run freely at full speed, and after certain interval, it takes the environmental parameters like room temperature, humidity, and time as inputs. After that, the system takes the decision and controls the speed of the fan.


2020 ◽  
pp. 344-344
Author(s):  
Andrii Radchenko ◽  
Ionut-Cristian Scurtu ◽  
Mykola Radchenko ◽  
Serhiy Forduy ◽  
Anatoliy Zubarev

The fuel efficiency of gas engines is effected by the temperature of intake air at the suction of turbocharger. The data on dependence of fuel consumption and engine electric power on the intake air temperature were monitored for Jenbacher gas engine JMS 420 GS-N.LC to evaluate its influence. A waste heat of engine is rejected for heating water to the temperature of about 90??. The heat received is used in absorption lithium-bromide chiller to produce a cold in the form of chilled water. A cooling capacity of absorption chiller firstly is spent for technological needs and then for feeding the central air conditioner for cooling the ambient air incoming the engine room, from where the air is sucked by the engine turbocharger. The monitoring data revealed the reserves to enhance the efficiency of traditional cooling system of intake air by absorption chiller through deeper cooling. This concept can be realized in two ways: by addition cooling a chilled water from absorption chiller to about 5-7?? for feeding engine intake air cooler or by two-stage cooling with precooling ambient air by chilled water from ACh in the first stage and subsequent deep cooling air to the temperatures 7-10?? in the second stage of intake air cooler by using a refrigerant as a coolant. In both cases the ejector chiller could be applied as the most simple in design.


2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Haitham M. Bahaidaraha ◽  
Mohand H. Mohamed ◽  
Esmail M. A. Mokheimer

In hot and humid climates, air conditioning is an energy-intensive process due to the latent heat load. A unitary air conditioner system is proposed, here, to reduce the latent heat of the humid air using a liquid desiccant followed by an evaporative cooling system. The heat liberated by the desiccant is removed by a solution to the solution heat exchanger. To restore the concentration of the liquid desiccant, the desiccant solution is regenerated by any low-temperature heat source such as solar energy. In order to make the system compact, the membrane heat exchanger is used for the dehumidifier and regenerator. This paper presents the numerical investigation of heat and mass transfer characteristics of a selected membrane dehumidifier under different climatic parameters. Membrane-based parallel-plate and hollow-fiber exchangers are used for this application. A parallel-plate heat-and-mass exchanger (contactor) is composed of a series of plate-type membrane sheets to form channels. On the other hand, hollow-fiber membranes are packed in a shell to form a shell-and-tube heat-and-mass exchanger. The two streams of both contactors are in a counter parallel flow, separated by micro-porous semi-permeable hydrophobic membranes. In this research, the equations governing the transport of heat and mass between the two streams along with the membrane effect in both contactors are solved numerically. The results are compared at different number-of-transfer units (NTU) on the airside and thermal capacity ratios. It is found that the hollow fiber is more efficient than the parallel plate.


2009 ◽  
Vol 32 (1) ◽  
pp. 70-77 ◽  
Author(s):  
Sung Chul Kim ◽  
Jong Phil Won ◽  
Yong Sun Park ◽  
Tae Won Lim ◽  
Min Soo Kim

Author(s):  
Phil Paik ◽  
Vamsee K. Pamula ◽  
Krishnendu Chakrabarty

Thermal management is becoming an increasingly important issue in integrated circuit (IC) design. The ability to cool ICs is quickly reaching a limit with today’s package-level solutions. While a number of novel cooling methods have been introduced, many of which are microfluidic approaches, these methods are unable to adaptively address the uneven thermal profiles and hot-spots generated in high performance ICs. In this paper, we present a droplet-based digital microfluidic cooling system for ICs that can adaptively cool hot-spots through real-time reprogrammable flow. This paper characterizes the effectiveness of microliter-sized droplets for cooling by determining the heat transfer coefficient of a droplet shuttling back and forth in an open system over a hot-spot at various speeds. Cooling is found to be significantly enhanced at higher flow rates of droplets. In order to further enhance cooling, the effect of varying droplet aspect ratio (width/height) in a confined system was also studied.


1996 ◽  
Vol 118 (1) ◽  
pp. 16-21 ◽  
Author(s):  
S. M. Aceves

This paper shows an analysis of the applicability of an adsorption system for electric vehicle (EV) air conditioning. Adsorption systems are designed and optimized to provide the required cooling for four combinations of vehicle characteristics and driving cycles. The resulting adsorption systems are compared with vapor compression air conditioners that can satisfy the cooling load. The objective function is the overall system weight, which includes the cooling system weight and the weight of the battery necessary to provide energy for air conditioner operation. The system with the minimum overall weight is considered to be the best. The results show the optimum values of all the variables, as well as temperatures and amounts adsorbed, for the adsorption and desorption processes. The results indicate that, for the conditions analyzed in this paper, vapor compression air conditioners are superior to adsorption systems, not only because they are lighter, but also because they have a higher COP and are more compact.


Author(s):  
Kourosh Mousavi Takami ◽  
Jafar Mahmoudi

Hot spot temperature (HST) is the most important parameter in the operation of power transformers. The HST has to be held under a prescribed limit. HST has a considerable effect on the insulation aging. Therefore detecting, monitoring and removing the HST could be a very important and necessary action for utilities. A new design of oil spraying and its effect, along with a thermal management in a transformer cooling system has been studied in this paper. The effect of oil fluid flow on the HST problem has been considered in this paper; and the calculations and simulation have been performed by Ants algorithm. The simulation results have been validated based on a 230/63/20 kV, 250MVA transformer at the Sari substation in Iran, and the results indicate that the new design could mitigate the limitations of transformer loading due to the HST problem. The Ants algorithm have been proposed and applied for accomplishing this task and to give an improved level of accuracy.


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