scholarly journals Investigation of thermal efficiency of previously investigated types of thermal insulation in the simplified flow part of the heat exchanger and a full-fledged model of the recuperative heat exchanger

Author(s):  
A. M. Kalashnikov ◽  
◽  
I. D. Obukhov ◽  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Manuel S. Krommweh ◽  
Wolfgang Büscher

AbstractExhaust air treatment systems (EATS) are used in animal husbandry to reduce emissions. However, EATS are associated with high acquisition and operating costs. Therefore, a plant technology is being developed that integrates a recuperative heat exchanger into a biological air scrubber. The overall aim is to reduce total costs of livestock buildings with EATS by saving heating costs and to improve animal environment. In this study, a special pilot-plant on a small-scale, using clean exhaust air, was constructed to evaluate the heating performance on laboratory scale. Three assembly situations of the heat exchanger into trickle-bed reactor were part of a trial with two different defined air flow rates. In all three assembly situations, preheating of cold outside air was observed. The heating performance of the assembly situation with the sprayed heat exchanger arranged below showed an average of 4.4 kW at 1800 m3 h−1 (outside air temperature range 0.0–7.9 °C). This is up to 18% higher than the other two experimental setups. The heating performance of the pilot-plant is particularly influenced by the outside air temperature. Further research on the pilot-plant is required to test the system under field conditions.


2012 ◽  
Author(s):  
Sharifah Rafidah Wan Alwi ◽  
Muhammad Azan Tamar Jaya ◽  
Zainuddin Abdul Manan

Kilang penapisan minyak sawit lazimnya melibatkan proses penggunaan tenaga yang tinggi. Peningkatan kecekapan tenaga adalah amat penting bagi memastikan keuntungan tercapai. Kertas kerja ini menggunakan teknik analisis jepit bagi memaksimumkan penggunaan semula haba dan meningkatkan kecekapan sistem rangkaian haba sedia ada di kilang penghasilan minyak sawit, tertakluk kepada kekangan–kekangan proses. Langkah–langkah yang terlibat ialah penetapan sasaran guna semula haba maksimum diikuti dengan reka bentuk rangkaian haba yang ekonomik. Aplikasi teknik berkenaan kepada kilang penghasilan minyak sawit telah menghasilkan pengurangan penggunaan haba panas dan sejuk sebanyak 700 kW (21%), atau penjimatan kos utiliti sebanyak RM370,787, dengan pelaburan kapital sebanyak RM656,293 dan jangka pulangan balik selama 1.77 tahun. Kata kunci: Analisis jepit; minyak kelapa sawit; sedia ada; rangkaian pemindahan haba; kitar semula haba maksimum A palm oil refinery involves energy–intensive processes. Maximizing thermal efficiency of palm oil refinery is crucial for the plant profitability. This work implements a pinch analysis retrofit technique to maximize heat recovery and thermal efficiency of a palm oil refinery, subject to the existing process constraints. The procedures involve setting the maximum heat recovery targets and cost–effective retrofit of the heat exchanger network (HEN). Application of the technique on a palm oil refinery results in reduction of 700 kW (21%) heating and cooling loads or a saving of RM370,787, incurring a capital investment of about RM656,293 and a payback period of 1.77 years. Key words: Pinch analysis; palm oil; retrofit; heat exchanger network; maximum heat recovery


2021 ◽  
Vol 11 (1) ◽  
pp. 46-55
Author(s):  
Arman B. KOSTUGANOV ◽  
Vitaly V. DEMIDOCHKIN

This article discusses the issue of determining the value the average wall temperature of the plate of a recuperative heat exchanger type “air-to-air” with a corrugated mesh insert based on the results processing the data of a physical experiment to determine the thermohydraulic characteristics such heat exchange surfaces. It has been established that the temperature fi eld of heat exchange surfaces of this type is nonuniform, depends on the conditions of heat exchange and hydraulic regimes of air fl ow. Therefore, the adoption of the arithmetic means value of the measured surface temperatures as the calculated average temperature of the heat exchanger wall entails signifi cant errors in the subsequent processing of experimental data and fi nal the values of the heat transfer coeffi cients, the values the Nusselt criterion and the criterion equations of heat transfer. It is proposed to determine the average value the wall temperature of the heat exchanger based on the results of measurements the wall’s temperatures, the estimate of the coordinates the center of distribution the results of measurements the wall temperatures, the equations of heat balance and heat transfer.


2020 ◽  
Vol 19 (4) ◽  
pp. 43-57
Author(s):  
H. H. Omar ◽  
V. S. Kuz'michev ◽  
A. O. Zagrebelnyi ◽  
V. A. Grigoriev

Recent studies related to fuel economy in air transport conducted in our country and abroad show that the use of recuperative heat exchangers in aviation gas turbine engines can significantly, by up to 20...30%, reduce fuel consumption. Until recently, the use of cycles with heat recovery in aircraft gas turbine engines was restrained by a significant increase in the mass of the power plant due to the installation of a heat exchanger. Currently, there is a technological opportunity to create compact, light, high-efficiency heat exchangers for use on aircraft without compromising their performance. An important target in the design of engines with heat recovery is to select the parameters of the working process that provide maximum efficiency of the aircraft system. The article focused on setting of the optimization problem and the choice of rational parameters of the thermodynamic cycle parameters of a gas turbine engine with a recuperative heat exchanger. On the basis of the developed method of multi-criteria optimization the optimization of thermodynamic cycle parameters of a helicopter gas turbine engine with a ANSAT recuperative heat exchanger was carried out by means of numerical simulations according to such criteria as the total weight of the engine and fuel required for the flight, the specific fuel consumption of the aircraft for a ton- kilometer of the payload. The results of the optimization are presented in the article. The calculation of engine efficiency indicators was carried out on the basis of modeling the flight cycle of the helicopter, taking into account its aerodynamic characteristics. The developed mathematical model for calculating the mass of a compact heat exchanger, designed to solve optimization problems at the stage of conceptual design of the engine and simulation of the transport helicopter flight cycle is presented. The developed methods and models are implemented in the ASTRA program. It is shown that optimal parameters of the working process of a gas turbine engine with a free turbine and a recuperative heat exchanger depend significantly on the heat exchanger effectiveness. The possibility of increasing the efficiency of the engine due to heat regeneration is also shown.


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