IMPROVING THE EFFICIENCY OF HEAT TRANSFER IN THE PROPANE AIR CONDENSER

A variant of reconstruction of the tube bundle of an air-cooling apparatus designed for propane con-densation is considered in order to increase the intensity of heat transfer from the outer surface of finned tubes to atmospheric air.

Experimental study of the solid fouling effect on the air-cooled apparatus characteristics

External fouling on the heat exchange surface of air-cooled apparatus are formed during operation, which leads to a significant increase in energy consumption and deviations from the optimal operating mode of the entire system. This phenomenon is a problem for all energy conversion systems. This paper presents the experimental study results of a complex of a commercial cooled object with real fouling on the air condenser surface. To study the effect of fouling, an experimental bench was developed – a single-stage refrigerating machine that provides cold supply to a thermostatic chamber. Three types of fouling were used: sand, fluff and dust. Fouling were picked from the operating condensers and identical in the type of heat exchange surface to the experimental sample. With a change in the quantitative and qualitative composition of the fouling, the air condenser thermal and aerodynamic characteristics and the energy efficiency of the machine as a whole were determined. The experiment showed that at maximum fouling of the heat exchange surface with sand and fluff, air movement stops. This means that at a certain thickness of sand and fluff layer, an air impermeable dense structure is formed. Dust with the same form of filling the free space for the flow remains permeable to air. Experiments showed that the qualitative composition of the fouling is the main factor that determines the heat exchanger performance. It was found that from the experimental set of fouling, roadside dust has the greatest negative effect on the condenser characteristics and the machine as a whole. The aerodynamic properties of the heat exchanger depend to some extent on the qualitative composition of the fouling. As a conclusion, it was suggested that the process nature of air flow passing through the investigated fouling can be described as gas flows in porous media.

INFLUENCE OF THERMAL RESISTANCE OF AIR CONDENSER TUBES ON STEAM COOLING EFFICIENCY

The research is carried out using a mathematical model of conditions and features of condensation processes with the influence of changes in internal and external thermal resistances of working bodies, which occur during contamination of outside and inside metal pipes of heat exchange surfaces of air condenser. capacitor. Particular attention is paid to the selection, detailing and determination of more than twenty basic parameters that characterize the operation of the direct cooling unit of the condensing unit for the summer, the conditions of heat transfer processes between the working bodies taking into account the finned outer surface of elliptical condenser tubes. The results of experiments on the mathematical model are analyzed and the influence of the incoming air velocity and ambient temperature on the output steam pressure in the condenser direct air cooling system within the change of internal and external thermal resistances in the range 0-0.001(m2·K)/W due to cooling tube contamination is determined. air condenser steam turbine installation. Conditions, character and features of influence of thermal resistance of pollution in cooling tubes on steam pressure at an exit from them are defined, the basic factors defining steam pressure at an exit, necessity of the organization of control of thermal resistance of pollution in a pipe during unit operation at variable operating conditions and expediency is substantiated. conducting test studies of operating modes while taking into account the influence of thermal resistance of external and internal pollution on the thermal efficiency of the cooling unit. Studies have shown that at a fixed value of the heat load of the exhaust steam, the pressure of the steam outlet increases with increasing ambient temperature and decreasing the speed of the incoming air.

Prototype’s seizing and design of a solar refrigerator based on solid adsorption

Solar refrigerator machines based on solid adsorption present a highly interesting solution to the Industry of Cooling Production. In one hand, they are significantly attractive economy ways because of the abundance of the solar energy resources. In the other hand, they are environment friendly. As a result, these machines could present one of the most competitive solutions to the improvement of this very industry. The aim of this paperwork is to provide an accurate study on how to design, seize and build a prototype of an adsorption solar refrigerator using activated-carbon/ammonia pair: Firstly, we used a static model, which is based on the use of state equations (vapor/liquid) at thermodynamic equilibrium. This model computes the cycled mass and the cycle coefficient of performance (COPc) for each four characteristic temperatures of the cycle. Secondly, we develop a dynamic simulation program based on conservation equations of energy and mass in the reactor, this program allow the calculation of the temperature, the pressure inside the reactor, the adsorbed mass and the solar coefficient of performance (COPs). Finally, in the light of our results, we design this prototype, it would consist of the reactor: a solar panel, size 1 m2contain tubes with a diameter of 10cm, an air condenser, and a cold chamber containing an air evaporator.

Algorithm for calculation of a CCGT of a trinary type with an air condenser

In this paper, an algorithm and a program have been developed that make it possible in a complex to calculate the combined operation of a combined-cycle gas turbine (CCGT) and air condenser (AC), as a result of which it is possible to investigate their operation and performance, depending on a large number of operating parameters.

Improvement air condensers evaluation model

The results of analysis of the literature on the calculation of the heat transfer coefficient of an air condenser in the flow past a bundle of finned tubes by an air flow. The methods of calculation are disassembled, marked advantages and disadvantages of each. Calculations of the heat transfer coefficient for each method are given; the results compared with the experimental data.

The Analysis of an Air Condenser’s Performance in Russia's High Northern Climate

This paper briefly describes the main issues that are happening due to the usage of traditional systems of technical water supply at power plants, both from operational and environmental points of view. The article also presents an alternative option, as an air condenser, and the analysis of the using of such technology.