Kemal Çomaklı - Academia.edu (original) (raw)

Papers by Kemal Çomaklı

Applied Thermal Engineering, 2016

Abstract In this study, we examined the event of condensing water vapour in flue gas in order to ... more Abstract In this study, we examined the event of condensing water vapour in flue gas in order to recoverthe latent heat that is carried by exhaust flue gas in 60 MW natural-gas fired district heating system of a university. With this, we aimed to design theoretically a waste heat recovery unit and conduct an economic analysis of it. For this study, actual operation data of the system were taken. In the design calculations of flue gas condenser, we used one-dimensional Finite-difference Method and made a computer programme. According to calculation results, exhaust flue gas temperature can be decreased to 40 °C with a flue gas condenser that has 80 m 2 surface area and is made of 316 quality stainless steel horizontal plain tube bundles. Annual fuel saving was calculated as $ 407,396.16 with Annual Equivalent Analysis Method.

Applied Thermal Engineering, 2017

In this study, energy and exergy analyses of natural gas fired boilers in a district heating syst... more In this study, energy and exergy analyses of natural gas fired boilers in a district heating system are performed. Mass, energy and exergy balance equations are formed for the boilers and its components. In the boilers, energy or heat losses are examinated, and the biggest of these is identified as the heat loss of flue gases. Energy and exergy efficiencies of the heating system are researched, and the energy, exergy flow diagrams are illustrated by specifying locations of irreversibilities. According to the results of the analyses, the ratio of flue gas energy and exergy losses in the boilers are 16.81% and 6.14%, respectively. The energy and exergy efficiences of the boilers are found to be 82% and 32.78%. The location, where the maximum of the irreversibility in the boilers is noticed as combustion chamber, and adiabatic combustion temperature is calculated as 1846 °C.

Mühendis ve makina, 2006

... gün biraz daha arttırmıştır. keşfedilmesine kadar sürmüştür. Kemal ÇOMAKLI, Fadime ŞİMŞEK, Öm... more ... gün biraz daha arttırmıştır. keşfedilmesine kadar sürmüştür. Kemal ÇOMAKLI, Fadime ŞİMŞEK, Ömer ÖZYURT, Kadir BAKIRCI Atatürk Üniversitesi Mühendislik Fakültesi Makina Mühendisliği Bölümü ÖZET ... etmiştir.[2] temelinde, CFC&amp;#x27;nin doğası gereği sahip olduğu ve ...

Mühendis ve makina, Sep 13, 2015

Mühendis ve makina, Sep 2, 2015

Bu çalışmada, atık baca gazından ısı geri kazanımı için bir sistem tasarlanmıştır. Geri kazanılan... more Bu çalışmada, atık baca gazından ısı geri kazanımı için bir sistem tasarlanmıştır. Geri kazanılan bu ısının, kazan yakma havasının ön ısıtılması için kullanımı düşünülmüştür. Bu sebeple, 60 MW'lık bir bölgesel ısıtma sisteminin gerçek işletme verileri kullanılmıştır. Sistemin tasarım hesapları ve ekonomik analizi yapılmıştır. Hesaplamalar bu sistemin baca gazından ısı geri kazanım potansiyelinin %1,3'e erişebileceğini göstermektedir. Sistemin geri ödeme süresi 5 ay olarak hesaplanmıştır.

Journal of The Energy Institute, Dec 1, 2008

In this paper, energy efficiency and life cycle cost economic analysis of conventional and conden... more In this paper, energy efficiency and life cycle cost economic analysis of conventional and condensing natural gas fired combi boilers in the individual heating systems are evaluated. The exit flue gas temperature of a conventional gas fired boiler is usually high and a great amount of heat energy is lost to the environment. In the flue gas, both sensible heat and latent heat can be recovered by adding a condensing heat exchanger. Thus, the condensing combi boiler efficiency can be increased by as much as 10%. For this purpose, equations of annual fuel consumption and condensed water vapour quantity are identified and also life cycle costs method has been used to analyse the feasibility of both combi boilers. It is found that condensing combi boiler can provide fuel saving y8% in comparison to conventional combi boiler in individual heating systems. In addition, the life cycle cost analysis showed that condensing combi boiler is cheaper than conventional combi boiler.

Applied Thermal Engineering, Apr 1, 2004

Environmental problems caused by energy using threaten the world. High CO 2 emissions emitted int... more Environmental problems caused by energy using threaten the world. High CO 2 emissions emitted into the atmosphere by combustion of fossil fuels cause global warming. Result of combustion of fossil fuels used for heating buildings, air pollution occurs much more in cold cities like Erzurum. Erzurum is one of the coldest cities of Turkey. Low quality fuel consumption together with the increasing energy demands for space heating have caused very high air pollution and poor air quality on occasion during heating period in Erzurum. Thus, in this work, we investigated environmental impact of heat insulation used for reduction heat losses in building. In this analysis, it has been determined that CO 2 emissions amount decreased 50% by means of optimum insulation thickness used and other energy savings methods in buildings.

Isı Bilimi ve Tekniği Dergisi, 2010

The goal of this work is to determine the optimum set of parameters by using the Taguchi method i... more The goal of this work is to determine the optimum set of parameters by using the Taguchi method in vapour compression heat pump systems. The experimental apparatus consist of an air-to-liquid vapor compression heat pump, a water cooled condenser, a forced air evaporator, an electrical air and water heaters, and various measuring elements and other auxiliary equipments. Refrigerants R22, R407C, and five of their binary mixtures which contain about 0%, 25%, 50%, 75%, and 100% mass fractions of R407C were tested. To determine the effect of the chosen parameters on the system and optimum working conditions, an experimental design method suggested by Genichi Taguchi was used. The most effective parameters are found to be the condenser water mass flow rate for the coefficient of performance and to be condenser water inlet temperature for the exergetic efficiency.

International Journal of Automotive and Mechanical Engineering, Jun 30, 2014

In this study a detailed exergetic analysis is made of the components of heat pumps by changing t... more In this study a detailed exergetic analysis is made of the components of heat pumps by changing the heat source and heat sink fluid as either water or air. To realize this aim a multifunctional heat pump test system was used, which can be run in four modes, air to air, air to water, water to air and water to water, using one compressor. When the system is run in water to air mode compressor exergy efficiency reaches its highest value. When the system is run in air to water mode the exergy efficiency of the compressor falls to its lowest value. In the heat pump's water to air mode the exergy destruction rate of the compressor becomes minimal. Exergetic performance of the condenser is best when the system is run in water to air mode. When the system runs in air to air mode, the exergy destruction rate of the condenser is at maximum, and falls to minimum when the system runs in air to water mode. Water to water is the running mode in which evaporator exergy efficiency is the best. Exergy efficiency of the evaporator decreases when the temperature of the evaporator fluid increases. Maximum compressor exergy efficiency increases according to an increase of mass flow rate is seemed in the air to air mode. The heat pump mode in which the exergy destruction rate of the compressor is minimal, is water to air mode. The running modes in which the condenser and compressor work with maximum and minimum efficiency are the same: water to air, and air to water modes. The compressor is the component which has maximum exergy efficiency with an average of 61.04% for all tests. Exergy efficiency of the condenser is lowest for all tests with an average of 14.25%

Applied Thermal Engineering, Jul 1, 2016

h i g h l i g h t s An air to water heat pump was designed to make an exergetic comparative inves... more h i g h l i g h t s An air to water heat pump was designed to make an exergetic comparative investigation. It is operated with R22 and uses a scroll compressor. A detailed exergy analysis is made for components and heat pump system. The relation between the exergetic performances of components and heat pump is investigated.

Energy, Sep 1, 2013

In this study, we designed a multifunctional heat pump system using just one scroll compressor an... more In this study, we designed a multifunctional heat pump system using just one scroll compressor and which can be run in four different modes, namely air to air, air to water, water to water and water to air, in order to make an experimental energetic and exergetic performance comparison. Experimental system consists of two condensers and two evaporators and uses R22 as working fluid. One of the evaporators and condensers uses water and the others use air as heat source/sink. Heating capacities of four heat pump types are equal to each other. It is realized by adjusting the mass flow rate and temperature level of external fluid of condenser. Results show that the heat pump unit which has the maximum COP (coefficient of performance) value is water to air type with 3.94 and followed by water to water type with 3.73, air to air type with 3.54 and air to water type with 3.40. Ranking of four heat pump types with respect to their mean exergy efficiency is as follows; water to air type with 30.23%, air to air type with 30.22%, air to water type with 24.77% and water to water type with 24.01%. Exergy destruction rates of the systems were investigated in this study and the results revealed that the heat pump type which has the maximum exergy destruction is air to air type with 2.93 kW. The second highest one is air to water type with 2.84 kW. The third highest one is water to air type with 2.64 kW and last one is water to water type with 2.55 kW. It is understood that the temperature of the evaporator external fluid affects the exergetic efficiency of the system more than the mass flow rate. In contrast to the previous, the dominant parameter which has more important effect on the exergy destruction of the heat pump unit is the mass flow rate of evaporator external fluid.

Applied Energy, Nov 1, 2009

In this study, refrigerants R22 and R404A five of their binary mixtures which contain about 0%, 2... more In this study, refrigerants R22 and R404A five of their binary mixtures which contain about 0%, 25%, 50%, 75% and 100% mass fractions of R404A were tested. It is investigated experimentally the effects of gas mixture rate, evaporator air inlet temperature (from 24 to 32°C), evaporator air mass flow rate (from 0.58 to 0.74 kg/s), condenser air inlet temperature (from 22 to 34°C) and condenser air mass flow rate (from 0.57 to 0.73 kg/s) on the coefficient of performance (COP) and exergetic efficiency values of vapor compression heat-pump systems. To determine the effect of the chosen parameters on the system and optimum working conditions, an experimental design method suggested by Genichi Taguchi was used. In this study, it was observed that the most effective parameters are found to be the condenser air inlet temperature for COP and exergetic efficiency.

Applied Thermal Engineering, May 1, 2004

In this paper, energy and exergy losses forming in the heat distribution network of district heat... more In this paper, energy and exergy losses forming in the heat distribution network of district heating systems were evaluated. For this purpose, equations of energy and exergy losses were identified and by using them, heat distribution network of the university campus which has a heating network of pipes 11,988 m in length and 65-250 mm in diameter was analyzed. It was found that exergy losses forming during heat distribution were about 16% of total exergy in the system and temperature of hot water supplied and returning was found to be the most important factor affecting these exergy losses.

Energy, May 1, 2011

A heat pump system is the ideal way to extend the heat supply of existing oil or gas fired heatin... more A heat pump system is the ideal way to extend the heat supply of existing oil or gas fired heating system. Consumption costs are lowered through the use of free energy from the environment, and the dependence on fossils fuels simultaneously reduces. In order to investigate the performance of the solar-ground source heat pump system in the province of Erzurum having cold climate, an experimental setup was constructed. The experimental apparatus consisted of solar collectors, a ground heat exchanger (GHE), a liquidto-liquid vapor compression heat pump, water circulating pumps and other measurement equipments. In this study, the performance of the system was experimentally investigated. The experimental results were obtained from October to May of 2008e2009. The experimentally obtained results are used to calculate the heat pump coefficient of performance (COP) and the system performance (COPS). The coefficient of performance of the heat pump and system were found to be in the range of 3.0e3.4 and 2.7e3.0, respectively. This study also shows that this system could be used for residential heating in the province of Erzurum being a cold climate region of Turkey.

This research evaluated and compared the thermodynamic performance of heat pump systems which can... more This research evaluated and compared the thermodynamic performance of heat pump systems which can be run under two different modes as air to air and air to water by using only one compressor. To achieve this comparison an experimental performance study was made on a traditional vapor compressed heat pump system that can be run air to air mode and air to water mode by help of a valve. The experiments made under different thermal conditions. Thermodynamic performance of the systems are presented and compared with each other for different working conditions.

In this study, the effect of nanofluids on the pool film boiling was experimentally investigated ... more In this study, the effect of nanofluids on the pool film boiling was experimentally investigated at saturated condition under atmospheric pressure. For this purpose, four different water-based nanofluids (Al2O3, SiO2, TiO2 and CuO) with 0.1% particle volume fraction were prepared. To investigate the boiling heat transfer, a cylindrical rod with high temperature was used. The rod heated up to high temperatures was immersed into nanofluids. The center temperature of rod during the cooling process was recorded by using a K-type thermocouple. The quenching curves showed that the pool boiling heat transfer was strongly dependent on the nanoparticle materials. During the repetitive quenching tests, the cooling time decreased and thus, the film boiling vanished. Consequently, the primary reason of this was the change of the surface characteristics due to the nanoparticles deposition on the rod-s surface.