Comparison of two numerical approaches to the domestic hot water circuit in a combi boiler appliance

Atmaca, Ayşe Uğurcan; Erek, Aytunç; Altay, H. Murat

doi:10.1016/j.enbuild.2016.06.053

Cited by 15 publications

(13 citation statements)

References 23 publications

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“…where ∆x is the thickness of the insulation material (m) while k and h are the coefficients of thermal conductivity (W/mk) and surface heat transfer (W/m 2 k) respectively [38]. Hot water demand causes hot water to flow out of the tank which is consequently replaced by the same volume of cold water [39]. This flow of water in and out of the tank causes a drop in the average temperature, T hp , of the hot water in the tank [40].…”

Section: Heat Pump Water Heatermentioning

confidence: 99%

Optimal control of heat pump water heater-instantaneous shower using integrated renewable-grid energy systems

2017

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Developing countries are grappling with energy and water insecurity, impelling governments to encourage end-users to conserve and efficiently consume these vital resources. With water heating being among the largest energy users in residential buildings, it is imperative that the efficiency and conservation of both energy and water are achieved. Heat pump water heaters (HPWHs) are a superior choice in efficiently providing domestic hot water. However, there are still challenges in their optimal operation and high initial cost in developing nations. Further, since they are normally centrally located in a house, there are water and associated energy losses during hot water conveyance to the end-use, as the cold water has to be poured away. This paper introduces an optimal control strategy of a hybrid HPWH and instantaneous shower powered using integrated renewable energy systems. This strategy has the potential to save 23.4% and 19 l of energy and water in a day respectively, while also promising lower energy and water bills to the end users. Further economic benefit can be achieved through the sale of excess renewable energy back to the grid through an appropriate feed-in tariff.

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Section: Heat Pump Water Heatermentioning

confidence: 99%

Optimal control of heat pump water heater-instantaneous shower using integrated renewable-grid energy systems

2017

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“…Demand for hot water from the HPWH causes hot water to flow out of the reservoir which is consequently replaced by the same volume of cold water [52]. The flow of hot and cold water through the HPWH's reservoir leads to a drop in the average temperature, T hp , of hot water in the reservoir [53].…”

Section: Heat Pump Water Heatermentioning

confidence: 99%

Model predictive control of heat pump water heater-instantaneous shower powered with integrated renewable-grid energy systems

2017

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“…In the literature, the working modes of combi‐boilers are investigated numerically and experimentally. Atmaca et al developed two different numerical models and compared the time‐wise variations of the heat transfer rates and CH/DHW temperatures with the experimental measurements. In the first model, they have discretized the governing equations with using finite difference method, and in the second one, a commercial software Flowmaster is used.…”

Section: Introductionmentioning

confidence: 99%

A heat recovery unit with phase change material for combi‐boilers

2019

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A novel heat exchanger (HEX) with phase change material (PCM) is proposed to recover the waste heat from the flue gas of a combi‐boiler. The thermal energy that is recovered from the flue gas is stored within the PCM‐HEX when the combi‐boiler works in the central heating mode. The stored thermal energy is then released to pre‐heat the domestic water so that the combi‐boiler provides the domestic water at a required temperature more rapidly even in eco‐mode. A mathematical model is developed, and the discharging process of the PCM‐HEX is considered. The transient analyses are conducted to reveal the influences of the mass of PCM, the phase change temperature of the PCM, and the flow rate of the domestic water. It is found that the PCM‐HEX integrated combi‐boiler increases the domestic water temperature in the early period of the hot water demand. Results show that the water temperature increases as much as ΔT = 9.3°C and 19.2°C for the flow rates of 10 L/min and 3 L/min, respectively. Increasing the water temperature with the PCM‐HEX not only helps to reduce the waiting time of the end‐user but also improves the efficiency of the combi‐boiler and reduces the energy consumption.

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Comparison of two numerical approaches to the domestic hot water circuit in a combi boiler appliance

Cited by 15 publications

References 23 publications

Optimal control of heat pump water heater-instantaneous shower using integrated renewable-grid energy systems

Optimal control of heat pump water heater-instantaneous shower using integrated renewable-grid energy systems

Model predictive control of heat pump water heater-instantaneous shower powered with integrated renewable-grid energy systems

A heat recovery unit with phase change material for combi‐boilers

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