scholarly journals Environmental and Health Impacts of Domestic Hot Water (DHW) Boilers in Urban Areas: A Case Study from Turin, NW Italy

2020 ◽  
Vol 17 (2) ◽  
pp. 595 ◽  
Author(s):  
Marco Ravina ◽  
Costanza Gamberini ◽  
Alessandro Casasso ◽  
Deborah Panepinto
Keyword(s):  
Urban Areas ◽  
Renewable Energy Sources ◽  
Heat Pumps ◽  
Hot Water ◽  
Environmental Benefits ◽  
District Heating System ◽  
Domestic Hot Water ◽  
Residential Units ◽  
Yearly Average ◽  
The Impact

Domestic hot water heat pumps (DHW HPs) have spread fast in recent years in Europe and they now represent an interesting opportunity for implementing renewable energy sources in buildings with a centralized/district heating system, where DWH is generally produced by a gas boiler or an electric water heater. Replacing these appliances has several environmental benefits, including the removal of air pollution sources and the reduction of Green House Gasses (GHG) emissions. In this work, we present the techno-economic and environmental evaluation of implementing DHW HPs in Turin, where 66% of the DHW demand is covered by dedicated gas boilers. The impact of such boilers was assessed through numerical air dispersion modeling conducted with the software SPRAY (Aria Technologies, Paris, French). Results show that removing these sources would reduce yearly average concentrations of NOx up to 1.4 µg/m3, i.e., about 1% of monitored concentrations of NOx, with a benefit of 1.05 ÷ 15.15 M€/y of avoided health externalities. Replacing boilers with DHW HPs is always financially feasible with current incentives while, in their absence, it would be convenient for residential units with 3 cohabitants or more (51.22% of the total population), thanks to scale economies.

scholarly journals Impact of Domestic Hot Water Systems on District Heating Temperatures

Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4694
Author(s):  
Tina Lidberg ◽  
Thomas Olofsson ◽  
Louise Ödlund
Keyword(s):  
Low Temperature ◽  
District Heating ◽  
Heating System ◽  
Hot Water ◽  
Space Heating ◽  
Circulation System ◽  
District Heating System ◽  
Domestic Hot Water ◽  
Temperature Levels ◽  
The Impact

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.

scholarly journals Flexibility Estimation of Residential Heat Pumps under Heat Demand Uncertainty

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5709
Author(s):  
Zhengjie You ◽  
Michel Zade ◽  
Babu Kumaran Kumaran Nalini ◽  
Peter Tzscheutschler
Keyword(s):  
Energy Storage ◽  
Heat Pump ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Heat Pumps ◽  
Hot Water ◽  
Maximum Temperature ◽  
Heat Demand ◽  
Residential Units ◽  
The Impact

With the increasing penetration of intermittent renewable energy generation, there is a growing demand to use the inherent flexibility within buildings to absorb renewable related disruptions. Heat pumps play a particularly important role, as they account for a high share of electricity consumption in residential units. The most common way of quantifying the flexibility is by considering the response of the building or the household appliances to external penalty signals. However, this approach neither accounts for the use cases of flexibility trading nor considers its impact on the prosumer comfort, when the heat pump should cover the stochastic domestic hot water (DHW) consumption. Therefore, in this paper, a new approach to quantifying the flexibility potential of residential heat pumps is proposed. This methodology enables the prosumers themselves to generate and submit the operating plan of the heat pump to the system operator and trade the alternative operating plans of the heat pump on the flexibility market. In addition, the impact of the flexibility provision on the prosumer comfort is investigated by calculating the warm water temperature drops in the thermal energy storage given heat demand forecast errors. The results show that the approach with constant capacity reservation in the thermal energy storage provides the best solution, with an average of 2.5 min unsatisfactory time per day and a maximum temperature drop of 2.3∘C.

scholarly journals Heat Pump Use in Rural District Heating Networks in Estonia

2021 ◽  
Vol 25 (1) ◽  
pp. 786-802
Author(s):  
Kertu Lepiksaar ◽  
Kiur Kalme ◽  
Andres Siirde ◽  
Anna Volkova
Keyword(s):  
Heat Pump ◽  
Renewable Energy Sources ◽  
District Heating ◽  
Ambient Air ◽  
Heat Pumps ◽  
Hot Water ◽  
Rural District ◽  
Low Grade ◽  
The Impact ◽  
Heating Networks

Abstract District heating has proven to be an efficient way of providing space heating and domestic hot water in populated areas. It has also proven to be an excellent way to integrate various renewable energy sources (RES) into the energy system. In Estonia, biomass covers most of the heat demand, but carbon-intensive fuels are still used to cover peaks and lows. Heat pumps can be a good solution for rural areas, as there is usually plenty of land available for heat pump facilities. In addition, heat pumps require low-grade heat sources such as ambient air, groundwater, lakes, rivers, sea, sewage water, and industrial waste heat. One of the downsides of heat pumps is the need for large investments compared to boilers fired by natural gas and biomass, and electric boilers. This study examines the impact of heat pump use on consumer prices for district heating in rural district heating networks in Estonia.

scholarly journals Analysis and comparison of methods for the preparation of domestic hot water from district heating system, selected renewable and non-renewable sources in low-energy buildings

2018 ◽  
Vol 30 ◽  
pp. 03001
Author(s):  
Maciej Knapik
Keyword(s):  
Renewable Energy ◽  
Energy Demand ◽  
Renewable Energy Sources ◽  
District Heating ◽  
Heating System ◽  
Hot Water ◽  
Low Energy ◽  
Energy Sources ◽  
District Heating System ◽  
Domestic Hot Water

The article presents an economic analysis and comparison of selected (district heating, natural gas, heat pump with renewable energy sources) methods for the preparation of domestic hot water in a building with low energy demand. In buildings of this type increased demand of energy for domestic hot water preparation in relation to the total energy demand can be observed. As a result, the proposed solutions allow to further lower energy demand by using the renewable energy sources. This article presents the results of numerical analysis and calculations performed mainly in MATLAB software, based on typical meteorological years. The results showed that system with heat pump and renewable energy sources Is comparable with district heating system.

scholarly journals Local Heating Networks with Waste Heat Utilization: Low or Medium Temperature Supply?

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 954 ◽  
Author(s):  
Hanne Kauko ◽  
Daniel Rohde ◽  
Armin Hafner
Keyword(s):  
Low Temperature ◽  
Heat Pump ◽  
Urban Areas ◽  
Waste Heat ◽  
Local Heating ◽  
District Heating ◽  
Heat Pumps ◽  
Hot Water ◽  
Local Network ◽  
Medium Temperature

District heating enables an economical use of energy sources that would otherwise be wasted to cover the heating demands of buildings in urban areas. For efficient utilization of local waste heat and renewable heat sources, low distribution temperatures are of crucial importance. This study evaluates a local heating network being planned for a new building area in Trondheim, Norway, with waste heat available from a nearby ice skating rink. Two alternative supply temperature levels have been evaluated with dynamic simulations: low temperature (40 °C), with direct utilization of waste heat and decentralized domestic hot water (DHW) production using heat pumps; and medium temperature (70 °C), applying a centralized heat pump to lift the temperature of the waste heat. The local network will be connected to the primary district heating network to cover the remaining heat demand. The simulation results show that with a medium temperature supply, the peak power demand is up to three times higher than with a low temperature supply. This results from the fact that the centralized heat pump lifts the temperature for the entire network, including space and DHW heating demands. With a low temperature supply, heat pumps are applied only for DHW production, which enables a low and even electricity demand. On the other hand, with a low temperature supply, the district heating demand is high in the wintertime, in particular if the waste heat temperature is low. The choice of a suitable supply temperature level for a local heating network is hence strongly dependent on the temperature of the available waste heat, but also on the costs and emissions related to the production of district heating and electricity in the different seasons.

scholarly journals Life Cycle Assessment (LCA) of an Innovative Compact Hybrid Electrical-Thermal Storage System for Residential Buildings in Mediterranean Climate

2021 ◽  
Vol 13 (9) ◽  
pp. 5322
Author(s):  
Gabriel Zsembinszki ◽  
Noelia Llantoy ◽  
Valeria Palomba ◽  
Andrea Frazzica ◽  
Mattia Dallapiccola ◽  
...  
Keyword(s):  
Life Cycle Assessment ◽  
Life Cycle ◽  
Environmental Impact ◽  
Mediterranean Climate ◽  
Residential Buildings ◽  
Renewable Energy Sources ◽  
Storage System ◽  
Hot Water ◽  
Electrical Consumption ◽  
The Impact

The buildings sector is one of the least sustainable activities in the world, accounting for around 40% of the total global energy demand. With the aim to reduce the environmental impact of this sector, the use of renewable energy sources coupled with energy storage systems in buildings has been investigated in recent years. Innovative solutions for cooling, heating, and domestic hot water in buildings can contribute to the buildings’ decarbonization by achieving a reduction of building electrical consumption needed to keep comfortable conditions. However, the environmental impact of a new system is not only related to its electrical consumption from the grid, but also to the environmental load produced in the manufacturing and disposal stages of system components. This study investigates the environmental impact of an innovative system proposed for residential buildings in Mediterranean climate through a life cycle assessment. The results show that, due to the complexity of the system, the manufacturing and disposal stages have a high environmental impact, which is not compensated by the reduction of the impact during the operational stage. A parametric study was also performed to investigate the effect of the design of the storage system on the overall system impact.

scholarly journals Overall Efficiency of On-Site Production and Storage of Solar Thermal Energy

2021 ◽  
Vol 13 (3) ◽  
pp. 1360
Author(s):  
Teodora M. Șoimoșan ◽  
Ligia M. Moga ◽  
Livia Anastasiu ◽  
Daniela L. Manea ◽  
Aurica Căzilă ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Thermal Energy ◽  
Urban Areas ◽  
Renewable Energy Sources ◽  
Multicriteria Analysis ◽  
High Energy ◽  
Solar Thermal ◽  
Solar Thermal Energy ◽  
The Impact ◽  
And Storage

Harnessing renewable energy sources (RES) using hybrid systems for buildings is almost a deontological obligation for engineers and researchers in the energy field, and increasing the percentage of renewables within the energy mix represents an important target. In crowded urban areas, on-site energy production and storage from renewables can be a real challenge from a technical point of view. The main objectives of this paper are quantification of the impact of the consumer’s profile on overall energy efficiency for on-site storage and final use of solar thermal energy, as well as developing a multicriteria assessment in order to provide a methodology for selection in prioritizing investments. Buildings with various consumption profiles lead to achieving different values of performance indicators in similar configurations of storage and energy supply. In this regard, an analysis of the consumption profile’s impact on overall energy efficiency, achieved in the case of on-site generation and storage of solar thermal energy, was performed. The obtained results validate the following conclusion: On-site integration of solar systems allowed the consumers to use RES at the desired coverage rates, while restricted by on-site available mounting areas for solar fields and thermal storage, under conditions of high energy efficiencies. In order to segregate the results and support optimal selection, a multicriteria analysis was carried out, having as the main criteria the energy efficiency indicators achieved by hybrid heating systems.

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

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3350
Author(s):  
Theofanis Benakopoulos ◽  
William Vergo ◽  
Michele Tunzi ◽  
Robbe Salenbien ◽  
Svend Svendsen
Keyword(s):  
Low Temperature ◽  
Heat Loss ◽  
District Heating ◽  
Heating System ◽  
Hot Water ◽  
Heating Power ◽  
Circulation Loop ◽  
Space Heating ◽  
District Heating System ◽  
Domestic Hot Water

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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