Improving the Energy Efficiency of Residential Buildings by Using a Drain Water Heat Recovery System

Abstract

Continuously increasing energy prices, as well as the increasing number of legal stipulations, bring to the attention of scientists the necessity of finding solutions for energy saving by using different heat sources. According to the EU Action Plan, the highest potential of energy savings (27-30% until 2020) will be applied to the existing buildings. Under the circumstances of environmental issues, research on the use of secondary energy resources is of great interest, being a concern in the context of sustainable development. The aim of the present paper is to accumulate knowledge on how a drain water heat recovery unit using a heat pipe heat exchanger performs under different drain water flow profile scenarios. Researching how the intermittent behaviour of the drain water influences the performance for this type of system is important because it gives insight on how the system will perform in a real life situation. In this paper the authors investigated the performance of a heat recovery unit, from drain water heat recovery. Investigation of the heat recovery unit performance shows that the heat pipe has the capability to recover more than 30% of the available heat in the drain water, at the flow rates investigated (0.3 ÷ 0.5 m 3 /hour). The application of the presented solution shows that a heat recovery system of this type has the possibility to recover a large portion of the available heat if it has been achieved in those buildings where the hot water consumption is higher (housing complexes, university campus, hotels, swimming pool, sport and leisure, hospital/healthcare, restaurants, laundry, pharmaceutical manufacturing).

Impact of petroleum and non-petroleum indices on financial development in Oman

“…Domestic credit increases by 4.25% when oil GDP increases by 1%, while an increase in the service sector has led to a 1.38% improvement in financial development. These results prove that energy price instability has a significant impact on economic environment, as also found by Gabor et al (2017), in that energy prices significantly impact the preservation of other energy sources.…”

“…The linear relationship between oil prices and the gross domestic product (GDP) began to first lose importance when during the drop in oil prices in the second half of the 1980s and had a positive impact on economic activities; however, this impact was smaller than expected by linear models (Lardic and Mignon 2008). Volatility in energy prices has a significant impact on the economic environment, as found by Gabor et al (2017), in that energy prices affect the savings and preservation of other energy sources. As such, many developed countries have tried to change and update their policies on how to exploit environmental resources.…”

“…Several previous studies, such as those of Ajmi et al 2015, Calza et al (2006), Jiménez et al (2009), Köhler (2015), and Neelam (2014), discuss the generation of environmental wealth policies and sources of revenue. Several studies, such as those of Lardic and Mignon (2008), Gabor et al (2017), Ibrahim et al (2014), Brown and Yücel (2002), and Ferderer (1996), discussed the volatility of oil pricing policy and GDP or export revenues. Advanced technology is also a key variable in identifying energy sources and economic development (Oladosu 2009).…”

An assessment of the potential for shower water heat recovery

“…Besides providing a valuable source of water for non-potable purposes [22], greywater drained from sanitary facilities may also be used as a non-conventional source of energy, e.g. for water heating [23]. In order to recover the heat accumulated in greywater, appropriate installations built within buildings may include retention systems for waste or heated water as well as non-storage DWHR units.…”

An assessment of the influence of local conditions on the economic and environmental sustainability of drain water heat recovery systems

“…As the flow rate increases, the amount of water going down the drain also increases, hence more energy is recovered. For a constant incoming cold water temperature, the energy recovery increases with an increase in the temperature of the drain water(Gabor et al 2017;Henderson and Hewitt 2001;Torras et al 2016). The impact of shower length and flow rate of the shower head on the net present value (NPV) of three different configurations of the DWHRS was evaluated (Słyś and Kordana 2014).…”