Browsing by Author "Alptekin, Ersin"

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Citation - WoS: 5
Citation - Scopus: 4
Development of an integrated underfloor heating system model in TRNSYS and performance assessments
(Elsevier Ltd, 2024) Okan Gök; Nezir Yağız Çam; Ersin Alptekin; Mehmet Akif Ezan; Aytunç Erek; Gok, Okan; Alptekin, Ersin; Ezan, Mehmet Akif; Erek, Aytunc; Cam, Nezir Yagiz
In this study a transient model for a solar underfloor heating system with a sensible heat thermal energy storage (SHTES) system to meet the heating demand of a residential building is developed in TRNSYS software. As a novelty in the current model rather than using the built-in modules in the software an in-house MATLAB routine is implemented in TRNSYS to simulate the spatial and temporal variations inside a 2D slab-type SHTES tank. Long-term dynamic simulations are conducted to discuss the influences of the design and working parameters on the (i) energetic and exergetic performances (ii) solar fraction and (iii) CO2 emissions associated with the alternative underfloor heating systems. Parametric analyses are performed for climatically different locations such as Izmir (Csa: Hot-summer Mediterranean climate) and Erzurum (Dfb: Warm-summer humid continental climate). Variations in charging loop mass flow rates have minimal impact on the overall system performance in Izmir and Erzurum compared to other design and working parameters. The highest energy efficiencies of the solar-aided underfloor heating system for Izmir and Erzurum are achieved for a comfort temperature of 20 °C with 32.9 % and 24.6 % respectively. Regarding exergy efficiency the highest was determined as 4.04 % with a 23.5 °C comfort temperature in Izmir and 3.89 % with a comfort temperature of 20 °C in Erzurum. As a final result of the environmental assessments integrating solar SHTES especially with a natural gas-based auxiliary heater significantly reduces CO2 emissions by 99.6 % and 50.0 % in Izmir and Erzurum respectively. © 2024 Elsevier B.V. All rights reserved.
Citation - WoS: 14
Citation - Scopus: 15
Thermal behavior of a solar-assisted latent heat thermal energy storage unit on the heating season under variable weather conditions
(ELSEVIER, 2022) Nezir Yagiz Cam; Ersin Alptekin; Levent Bilir; Mehmet Akif Ezan; Alptekin, Ersin; Bilir, Levent; Ezan, Mehmet Akif; Cam, Nezir Yagiz
Due to the fossil-fuel-related climatic problems which got worse in recent decades the worldwide share of renewable energy has significantly increased. Even though solar energy is one of the most accessible renewables it has an intermittent nature throughout the day. Different energy storage techniques are implemented to resolve the intermittency problem and make solar-aided energy accessible when it is needed. Energy use in buildings has a huge share of total energy demand and heating/cooling demands are responsible for most energy consumption in buildings. In this study the performance of a solar-assisted latent heat thermal energy storage (LHTES) unit integrated with a heat pump is investigated during the heating season under variable weather conditions. Phase change materials (PCMs) with different melting temperatures (T-m) and latent heat of fusions (h(sf)) are studied and parametric simulations are conducted to examine the proposed systems' economic advantage and payback duration. Variable weather conditions are defined in simulations and seven consecutive day analyses are conducted to ensure that results are not dependent on the initial conditions. Results revealed that the PCM with T-m= 35 degrees C and h(sf) = 240 kJ/kg has a better thermal performance than the other alternatives i.e. T-m = 31 degrees C and 40 degrees C. The integration of the solar-aided LHTES unit with the heat pump increases the COP of the heat pump and the increment varies from 35% to 80% for heating months in Izmir. Such an improvement in COP reduces the operating costs related to the electricity consumption of the heating device significantly and the simple payback period of the combined system is determined to be approximately 13 years in Izmir.