Okan GÖK, Ayşe Uğurcan ATMACA, Aytunç EREK, Hürrem Murat ALTAY

PLAKALI ISI EŞANJÖRÜNÜN PARAMETRE TANIMI ODAKLI KOMBİ SICAK KULLANIM SUYU HATTININ TRNSYS MODELİ

Mahal ve sıcak kullanım suyu ısıtılması için kullanılan kombiler, yaygın olarak kullanılan ev aletlerindendir. Laboratuvar testlerinin ön değerlendirmesi için bir kombinin sıcak kullanım suyu devresinin modellenmesi, deneyler için harcanan zamanı, maliyeti ve enerjiyi azalttığı için oldukça önemlidir. Bu makalenin yazarları tarafından oluşturulan çeşitli modelleme yaklaşımları bulunmaktadır. Önceki çalışmalarda, cihazın sıcak kullanım suyu devresi Zamana Bağlı Sistem Simülasyon Aracı (TRNSYS 18) kullanılarak modellenmiştir ve ekonomik mod simülasyonları için deneysel ve sayısal veriler kullanılarak iyi bir uyum ortaya konmuştur. Mevcut TRNSYS modelinin dezavantajı, TRNSYS model kütüphanesinden seçilen bileşenlerin, plakalı ısı eşanjörünün UA (toplam ısı transfer katsayısı ve ısı transfer alanının çarpımı) girdisi ve ısı hücresi bloğunun ısı tutma etkisi gibi bazı parametre tanımlarının deneysel verilere bağımlı olmasıdır. Bu makalede, plakalı ısı eşanjörünün UA parametresi zamana bağlı değişken bir profil yerine sabit bir değer olarak tanımlanmıştır. Kombinin ekonomik çalışma modu simülasyonlarında, sıcak kullanım suyunun giriş ve çıkış sıcaklık farkı için kararlı ve kararsız süreçleri kapsayan ortalama mutlak hatalar, sabit ve değişken UA yaklaşımları altında 5 l/dk, 7 l/dk ve 8.7 l/dk için sırasıyla 0.46°C, 0.82°C ve 0.53°C olarak neredeyse sabit kalmıştır. Konfor çalışma modunun modeli, sabit UA yaklaşımının önemli bir uygulaması olarak birkaç deneysel veri ile oluşturulmuştur. Konfor modu simülasyonunda, sıcak kullanım suyu giriş ve çıkış sıcaklık farkı profilinin ortalama mutlak hatası 0.5°C'ye düşmektedir.

Anahtar Kelimeler:

Kombi, Zamana bağlı sistem simülasyonu, Plakalı ısı değiştiricisi (PID), Sıcak kullanım suyu (SKS), Konfor ve ekonomik (eco) çalışma modları, TRNSYS modeli, UA girdisi

TRNSYS MODEL OF THE COMBI BOILER DOMESTIC HOT WATER CIRCUIT WITH A FOCUS ON THE PARAMETER DEFINITION OF THE PLATE HEAT EXCHANGER

Combi boilers used for both space and domestic hot water heating are one of the common household appliances. Modelling the domestic hot water circuit of a combi boiler for the preliminary evaluation of the laboratory testing is of crucial importance since it decreases the time, cost, and energy spent on the trials. There are various modelling approaches established by the authors of this paper. Domestic hot water circuit of the appliance is modelled previously making use of the Transient System Simulation Tool (TRNSYS 18) and a good agreement is achieved with the experimental and numerical data for the economic mode simulations. The drawback of the current TRNSYS model is the dependence on the experimental data for some of the parameter definitions of the components selected from the TRNSYS library, i.e. UA (multiplication of the overall heat transfer coefficient and the heat transfer area) input of the plate heat exchanger and heat retention effect of the heat cell block. In this paper, a constant value is assigned to the parameter definition of UA instead of a time dependent varied profile. Mean absolute errors covering the steady-state and transient operating regions for the domestic hot water inlet and outlet temperature difference in economic mode simulations stay nearly the same around 0,46°C, 0,82°C, and 0,53°C for 5 l/min, 7 l/min, and 8,7 l/min, respectively, under constant and variable UA approaches. Comfort operating scheme model is established with a couple of experimental data as of the principal application of the constant UA approach. Mean absolute error of the overall domestic hot water inlet and outlet temperature difference profile decreases to 0,5°C in the comfort mode simulation.

Keywords:

Combi boiler, Transient system simulation, Plate heat exchanger (PHE), Domestic hot water (DHW), Comfort and economic (eco) operating modes, TRNSYS model, UA input,

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Andrés A. C. and López J. M. C., 2002, TRNSYS model of a thermosiphon solar domestic water heater with a horizontal store and mantle heat exchanger, Solar Energy, 72(2), 89-98.
Antoniadis C. N. and Martinopoulos G., 2019, Optimization of a building integrated solar thermal system with seasonal storage using TRNSYS, Renewable Energy, 137, 56-66.
Atmaca A. U., Erek A., and Altay H. M., 2015, Investigation of Transient Behaviour of Combi Boiler Type Appliances for Domestic Hot Water, Applied Thermal Engineering, 82, 129-140.
Atmaca A. U., Erek, A., and Altay, H. M., 2016, Comparison of Two Numerical Approaches to the Domestic Hot Water Circuit in a Combi Boiler Appliance, Energy and Buildings, 127, 1043–1056.
Boait P. J., Dixon D., Fan D., and Stafford A., 2012, Production efficiency of hot water for domestic use, Energy and Buildings, 54, 160–168.
Bourke G. and Bansal P., 2012, New test method for gas boosters with domestic solar water heaters, Solar Energy, 86 (1), 78-86.
Braas H., Jordan U., Best I., Orozaliev J., and Vajen K., 2020, District heating load profiles for domestic hot water preparation with realistic simultaneity using DHWcalc and TRNSYS, Energy, 201, 117552.
BS EN 13203-1:2006, 2006, Gas-fired domestic appliances producing hot water- Appliances not exceeding 70 kW heat input and 300 l water storage capacity - Part 1: Assessment of performance of hot water deliveries.
Fridlyand A., Guada A. B., Kingston T., and Glanville P., 2021, Modeling modern, residential, combined space and water heating systems using EnergyPlus, ASHRAE Transactions, 127, 135-142.
Gök O., Atmaca A. U., Altay H. M., and Erek A., 2022, The Use of TRNSYS as a Simulation Tool for the Domestic Hot Water Performance Evaluations of the Combi Boilers, Proceedings of the 2nd International Conference on Energy, Environment and Storage of Energy, Kayseri, 96-97.
Gök O., Atmaca A. U., Altay H. M., and Erek A., 2023, Model of the Combi Boiler Appliance in TRNSYS for Domestic Hot Water Circuit: Experimental and Numerical Validations of Economic Mode Simulations, International Journal of Energy Studies, 8(1), 15-38.
Haissig C. M. and Woessner M., 2000, An adaptive fuzzy algorithm for domestic hot water temperature control of a combi-boiler, HVAC&R Research, 6:2, 117-134.
Harrabi I., Hamdi M., Bessifi A., and Hazami M., 2021, Dynamic modeling of solar thermal collectors for domestic hot water production using TRNSYS, Euro-Mediterranean Journal for Environmental Integration, 6:21.
Ibrahim O., Fardoun F., Younes R., and Louahlia-Gualous H., 2014, Review of water-heating systems: General selection approach based on energy and environmental aspects, Building and Environment, 72, 259-286.
Incropera F. P., Dewitt D. P., Bergman T. L., and Lavine A. S., 2007, Fundamentals of heat and mass transfer (6th ed.). USA: John Wiley & Sons, Inc.
Jordan U. and Vajen K., 2001, Influence of the DHW load profile on the fractional energy savings: A case study of a solar combi-system with TRNSYS simulations, Solar Energy, 69, 197-208.
Klein S. A. et al, 2017, TRNSYS 18: A Transient System Simulation Program, Solar Energy Laboratory, University of Wisconsin, Madison, USA, http://sel.me.wisc.edu/trnsys.
Lu M., Zhang C., Zhang D., Wang R., Zhou Z., Zhan C., Zai X., and Jing Q., 2021, Operational optimization of district heating system based on an integrated model in TRNSYS, Energy & Buildings, 230, 110538.
Nordlander S. G. and Persson T. G., 2003, Evaluation and computer modelling of wood pellet stoves with liquid heat exchanger, ISES World Conference, Gothenburg.
Pärisch P., Van der Veer N., Kirchner M., Giovannetti F., and Lampe C., 2019, Comfort assessment of tankless water heaters: Review and Suggestions, IEA SHC International Conference on Solar Heating and Cooling for Buildings and Industry.
Persson T., Fiedler F., Nordlander S., Bales C., and Paavilainen J., 2009, Validation of a dynamic model for wood pellet boilers and stoves, Applied Energy, 86(5), 645-656.
Persson T., Wiertzema H., Win K. M., and Bales C., 2019, Modelling of dynamics and stratification effects in pellet boilers, Renewable Energy, 134, 769-782.
Pomianowski M. Z., Johra H., Marszal-Pomianowska A., and Zhang C., 2020, Sustainable and energy-efficient domestic hot water systems: A review, Renewable and Sustainable Energy Reviews, 128, 109900.
Quintã A. F., Ferreira J. A. F., Ramos A., Martins N. A. D., and Costa V. A. F., 2019, Simulation models for tankless gas water heaters, Applied Thermal Engineering, 148, 944–952. Shrivastava R. L., Kumar V., and Untawale S. P., 2017, Modeling and simulation of solar water heater: A TRNSYS perspective, Renewable and Sustainable Energy Reviews, 67, 126–143.
Ucar M. and Arslan O., 2021, Assessment of improvement potential of a condensed combi boiler via advanced exergy analysis, Thermal Science and Engineering Progress, 23.
Villa-Arrieta M. and Sumper A., 2018, A model for an economic evaluation of energy systems using TRNSYS, Applied Energy, 215, 765–777.