On the possibilities to increase energy efficiency of domestic hot water preparation systems in existing buildings – Long term field research

Cholewa, Tomasz; Siuta-Olcha, Alicja; Anasiewicz, Rafał

doi:10.1016/j.jclepro.2019.01.138

Cited by 39 publications

(17 citation statements)

References 33 publications

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“…Roux et al [42] noted that, regardless of the need to reduce water heating costs, consumers want to have guaranteed stable access to warm water. Cholewa et al [43], on the other hand, emphasized the need to seek solutions that not only enable the reduction of energy consumption, but are also quick to install. Technological factors include the supply of systems dedicated to heat recovery from drain water.…”

Section: En Environmentalmentioning

confidence: 99%

Opportunities and Threats of Implementing Drain Water Heat Recovery Units in Poland

et al. 2019

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In recent years an increase of interest in usage of renewable energy sources as a substitution of fossil fuels is being noticeable. However, the waste heat potential, which can be used as an additional source of energy for heating water in buildings, is being omitted. The sources of this heat can be grey water discharged from such sanitary facilities as showers or washing machines. In response to this issue, we took on the task to define and analyze key factors affecting the development of DWHR (Drain Water Heat Recovery) systems using PESTLE (political, economic, social, technological, legal and environmental) analysis. The strengths and weaknesses of these systems were also identified. The studies were based on CFD (computational fluid dynamics) modeling tools. In the Autodesk Simulation CFD software environment, a DWHR unit was made, which was then analyzed for heat exchange efficiency. The obtained results were the basis for preparing the strategy for the development of Drain Water Heat Recovery systems. It was made using the SWOT/TOWS (strengths, weaknesses, opportunities and threats/threats, opportunities, weaknesses and strengths) method, which precisely orders information and allows presenting the project characteristic in readable way for a recipient. The results of the conducted analysis indicated the lack of acceptance on the part of potential users and the resulting need to promote the use of Drain Water Heat Recovery systems at residential level.

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Section: En Environmentalmentioning

confidence: 99%

Opportunities and Threats of Implementing Drain Water Heat Recovery Units in Poland

et al. 2019

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“…Circulation systems for DHW are also associated with large heat losses. A long-term study by Cholewa et al [31] found that the heat losses from hot water circulation in 12 different multi-family buildings in Poland varied between 56.7% and 70.5%. Another study made by Bøhm [32] showed that the losses from the circulation system were 23% to 70% in the studied apartment buildings, which also resulted in reduced cooling of the district heating water.…”

Section: Introductionmentioning

confidence: 99%

Impact of Domestic Hot Water Systems on District Heating Temperatures

2019

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When buildings become more energy effective, the temperature levels of district heating systems need to be lower to decrease the losses from the distribution system and to keep district heating a competitive alternative on the heating market. For this reason, buildings that are refurbished need to be adapted to suit low-temperature district heating. The aim of this paper is to examine whether four different energy refurbishment packages (ERPs) can be used for lowering the temperature need of a multi-family buildings space heating and domestic hot water (DHW) system as well as to analyse the impact of the DHW circulation system on the return temperature. The results show that for all ERPs examined in this study, the space heating supply temperature agreed well with the temperature levels of a low-temperature district heating system. The results show that the temperature need of the DHW system will determine the supply temperature of the district heating system. In addition, the amount of days with heating demand decreases for all ERPs, which further increases the influence of the DHW system on the district heating system. In conclusion, the DHW system needs to be improved to enable the temperature levels of a low-temperature district heating system.

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“…This is equivalent to a ratio of circulation loss to DHW use of two to three. A long-term investigation in 12 multi-family buildings in Poland found that the DHW circulation losses varied between 57% and 70% [26]. The ratio of circulation loss to the energy delivered for hot-water production can be from 25% in well-insulated systems to up to 300% in old buildings with poor pipe insulation.…”

Section: Circulation Heat Lossmentioning

confidence: 99%

Overview of Solutions for the Low-Temperature Operation of Domestic Hot-Water Systems with a Circulation Loop

et al. 2021

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The operation of typical domestic hot water (DHW) systems with a storage tank and circulation loop, according to the regulations for hygiene and comfort, results in a significant heat demand at high operating temperatures that leads to high return temperatures to the district heating system. This article presents the potential for the low-temperature operation of new DHW solutions based on energy balance calculations and some tests in real buildings. The main results are three recommended solutions depending on combinations of the following three criteria: district heating supply temperature, relative circulation heat loss due to the use of hot water, and the existence of a low-temperature space heating system. The first solution, based on a heating power limitation in DHW tanks, with a safety functionality, may secure the required DHW temperature at all times, resulting in the limited heating power of the tank, extended reheating periods, and a DH return temperature of below 30 °C. The second solution, based on the redirection of the return flow from the DHW system to the low-temperature space heating system, can cool the return temperature to the level of the space heating system return temperature below 35 °C. The third solution, based on the use of a micro-booster heat pump system, can deliver circulation heat loss and result in a low return temperature below 35 °C. These solutions can help in the transition to low-temperature district heating.

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On the possibilities to increase energy efficiency of domestic hot water preparation systems in existing buildings – Long term field research

Cited by 39 publications

References 33 publications

Opportunities and Threats of Implementing Drain Water Heat Recovery Units in Poland

Opportunities and Threats of Implementing Drain Water Heat Recovery Units in Poland

Impact of Domestic Hot Water Systems on District Heating Temperatures

Overview of Solutions for the Low-Temperature Operation of Domestic Hot-Water Systems with a Circulation Loop

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