Heat exchanger applications in wastewater source heat pumps for buildings: A key review

Culha, Oguzhan; Günerhan, Hüseyin; Bıyık, Emrah; Ekren, Orhan; Hepbaşlı, Arif

doi:10.1016/j.enbuild.2015.07.013

Cited by 107 publications

(69 citation statements)

References 19 publications

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“…Recently, energy generation from wastewater, e.g., due to heat recovery, attracts more attention internationally and several practical applications are documented in the international literature [1][2][3]. In a few countries as, for instance, Switzerland [4] and Germany [5] this energy source is already included in energy policy making.…”

Section: Introductionmentioning

confidence: 99%

Mapping Thermal Energy Resource Potentials from Wastewater Treatment Plants

et al. 2015

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Wastewater heat recovery via heat exchangers and heat pumps constitutes an environmentally friendly, approved and economically competitive, but often underestimated technology. By introducing the spatial dimension in feasibility studies, the results of calculations change considerably. This paper presents a methodology to estimate thermal energy resource potentials of wastewater treatment plants taking spatial contexts into account. In close proximity to settlement areas, wastewater energy can ideally be applied for heating in mixed-function areas, which very likely have a continuous heat demand and allow for an increased amount of full-load hours compared to most single-use areas. For the Austrian case, it is demonstrated that the proposed methodology leads to feasible results and that the suggested technology might reduce up to 17% of the Austrian global warming potential of room heating. The method is transferrable to other countries as the input data and calculation formula are made available. A broad application of wastewater energy with regard to spatial structures and spatial development potentials can lead to (1) increasing OPEN ACCESSSustainability 2015, 7 12989 energy efficiency by using a maximum of waste heat and (2) a significant reduction of (fossil) energy consumption which results in a considerable reduction of the global warming potential of the heat supply (GWP) if electricity from renewables is used for the operation of heat pumps.

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Section: Introductionmentioning

confidence: 99%

Mapping Thermal Energy Resource Potentials from Wastewater Treatment Plants

et al. 2015

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“…The system is composed of a connection with the bottom of the sewer pipe, a shaft equipped with a screen, an aboveground heat exchanger, and a heat pump. Different from other applications in which the heat pump is located directly in the sewer conduits [18,27], this solution foresees a shaft installed near the sewer bottom, connected purely by gravity. The shaft serves as a sump for the pump feeding the heat exchanger, and houses a coarse screen to avoid unwanted material carried by the wastewater from reaching the heat exchanger.…”

Section: Heat Recovery From Wastewatermentioning

confidence: 99%

Energy Recovery from Wastewater: A Study on Heating and Cooling of a Multipurpose Building with Sewage-Reclaimed Heat Energy

et al. 2019

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To achieve technically-feasible and socially-desirable sustainable management of urban areas, new paradigms have been developed to enhance the sustainability of water and its resources in modern cities. Wastewater is no longer seen as a wasted resource, but rather, as a mining ground from which to obtain valuable chemicals and energy; for example, heat energy, which is often neglected, can be recovered from wastewater for different purposes. In this work, we analyze the design and application of energy recovery from wastewater for heating and cooling a building in Brno (Czech Republic) by means of heat exchangers and pumps. The temperature and the flow rate of the wastewater flowing in a sewer located in the proximity of the building were monitored for a one-year period, and the energy requirement for the building was calculated as 957 MWh per year. Two options were evaluated: heating and cooling using a conventional system (connected to the local grid), and heat recovery from wastewater using heat exchangers and coupled heat pumps. The analysis of the scenarios suggested that the solution based on heat recovery from wastewater was more feasible, showing a 59% decrease in energy consumption compared to the conventional solution (respectively, 259,151 kWh and 620,475 kWh per year). The impact of heat recovery from wastewater on the kinetics of the wastewater resource recovery facility was evaluated, showing a negligible impact in both summer (increase of 0.045 • C) and winter conditions (decrease of 0.056 • C).Sustainability 2020, 12, 116 2 of 11 source of different types of energy: electrical energy from bioelectrochemical wastewater treatment processes [7,8], low-head hydroelectric energy [9], biogas from anaerobic digestion [10], renewable fuels from residual sludge processing [11,12], and heat energy [13]. The latter is particularly appealing in the framework of water-energy sustainable urban development; in particular, the heat energy recovery potential from wastewater could possibly be even higher than its recoverable chemical energy potential [14,15], and it does not require biological treatment to be converted into a directly usable form. Waste heat from wastewater is reportedly able to generate electrical energy via a thermoelectric generator [16], but the implementation of this is difficult within an urban context. A more accessible technology is the energy recovery from wastewater using heat exchangers installed directly in the sewage collection system [17]. A heat exchanger is installed in direct contact with the wastewater that serves as a heat source or sink, and is later connected to a heat pump and then to the heating and cooling system of a building situated in close proximity. Temperatures of civil wastewater may be more than 25-27 • C in domestic outflows [18], representing a significant thermal energy source [16]; at the inlet of water treatment plants or water resource recovery facilities (WRRFs), the temperature is far lower (15-25 • C or lower, depending on the climate) [16,19,20], and thus,...

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“…As a renewable heat source, urban sewage has many advantages [2,3]: (i) sewage contains almost 40% of the waste-heat energy discharged in cities; (ii) a large amount of sewage is discharged in cities every year; (iii) the sewage temperature is higher than outdoor air temperature in winter, and lower in summer, while the sewage temperature is relatively stable in a whole cooling or heating season. In China, the application of sewage source heat pump can be found in a multitude of cities, such as Beijing,…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, two special devices are required in the current application of sewage source heat pumps: One is anti-blockage device working like filter to filter the foulant out before the sewage entering heat exchanger; the other one is sewage heat exchanger which should have function of removing the fouling deposited on heat transfer surface. For anti-blockage devices, a number of prototypes and patents of sewage anti-blockage devices have appeared over the world: (1) in North European countries, the mechanical filtration (sieving) and the precipitation technique were used earlier, and in recent years, the grille-type conveyor and the four-way reversing backwash technology were applied in large sewage source heat pumps [5]; (2) in Japan, the automatic de-foulant filter, and the open type automatic rotary screen filter were developed [6]; (3) in China, several typical de-fouling devices were developed, such as the filter with continuously renewable surface 6 through high-velocity water [7], the rotating oval-tube sewage filter [8], and the semi-submerged rotary orifice plate sewage-source heat pump intake machine [9]. As for special heat exchangers with the function of removing the fouling deposited on the heat transfer surface, which were used in sewage source heat pump, some devices were reported in literature, such as (1) in Japan, the sewage heat exchanger with automatic cleaning system and the four-way reversing valve [6]; (2) in China, a novel dry-expansion evaporator with de-fouling function [10], and the sewage shell and tube heat exchangers with inner couplers springs decontamination device [8].…”

Section: Introductionmentioning

confidence: 99%