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.

A New Type of District Heating System Based on Distributed Absorption Heat Pumps

2009 ◽  
Author(s):  
Lin Fu ◽  
Yan Li
Keyword(s):  
Energy Consumption ◽  
Heat Pump ◽  
District Heating ◽  
Heating System ◽  
Heat Pumps ◽  
Hot Water ◽  
Conventional Heating ◽  
Low Grade ◽  
District Heating System ◽  
New Approach

This paper presents a new approach to utilize geothermal energy with absorption heat pump in district heating system. The heat pump is driven by the temperature-difference between primary and secondary heating loops. In this method, the low-grade thermal energy can be used in district heating system effectively, as a result, the heating capacity and energy efficiency of district heating system can be improved more than 20%. On one hand, it could relieve the existing dilemma (shortage) of central heat source, as well enhance the delivery capacity of heating network dramatically. On the other hand, heating cost may be reduced remarkably, due to the reduction in both coal consumption of central heat and energy consumption of delivery pump. Firstly, this paper introduces the district heating method based on distributed absorption heat pumps through the analysis on the parameter characteristics of low-grade energy, hot water of primary and secondary heating network, as well as the operation parameters of absorption heat pumps. Secondly, an economic and energy consumption analysis was discussed by comparing the new approach with conventional heating system. Finally, this paper presents several system configurations, discusses the operation strategies in various conditions, and proposes the operation modes for heating season.

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.

Electricity market options for heat pumps in rural district heating networks in Austria

Energy ◽  
2020 ◽  
Vol 196 ◽  
pp. 116875 ◽  
Author(s):  
O. Terreros ◽  
J. Spreitzhofer ◽  
D. Basciotti ◽  
R.R. Schmidt ◽  
T. Esterl ◽  
...  
Keyword(s):  
Electricity Market ◽  
District Heating ◽  
Heat Pumps ◽  
Rural District ◽  
Heating Networks

A Sustainable Trigeneration System for Residential Applications

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Azzam Abu-Rayash ◽  
Ibrahim Dincer
Keyword(s):  
Heat Pump ◽  
Storage Tank ◽  
Renewable Energy Sources ◽  
Water Storage ◽  
Hot Water ◽  
Low Grade ◽  
High Grade ◽  
Pump System ◽  
Water Storage Tank ◽  
Energy And Exergy

Abstract This paper features the integration of two renewable energy sources, making a new trigeneration system for residential applications. The system is primarily powered by solar photovoltaic-thermal (PVT) along with geothermal energy. This trigeneration system consists of a ground source heat pump, solar system, high-grade and low-grade heat exchangers, a heat pump system, and a water storage tank (WST). The objective of this system is to provide the main commodities for residential use including domestic hot water (DHW), electricity, and space heating. The system is analyzed energetically and exergetically using thermodynamic-based concepts. The overall energy and exergy efficiencies of the proposed system are found to be 86.9% and 74.7%, respectively. In addition, the energy and exergy efficiencies of the PVT system are obtained to be 57.91% and 34.19%, respectively. The exergy destructions at the high-grade heat exchanger and the water storage tank add up to 36.9 kW, which makes up 80% of the total exergy destruction of the system. Additionally, parametric studies are conducted to evaluate the degree of impact that various important parameters have on the overall system performance.

Expediency of substitution of water heating with air heating involving use of heat pumps

2019 ◽  
Vol 12 (1) ◽  
pp. 45-49
Author(s):  
A. V. Martynov ◽  
N. E. Kutko
Keyword(s):  
Heat Pump ◽  
Ambient Air ◽  
Heat Pumps ◽  
Low Grade ◽  
Heating Season ◽  
Water Heating ◽  
Heating Systems ◽  
Air Heating ◽  
Transformation Ratio ◽  
Air Temperatures

Expediency is considered of substitution of water heating and transition to air heating that can be implemented with “air-air” type heat pumps (HP). The absence of water pipelines raises the reliability of heating systems. In addition to improved reliability, heat pumping systems ensure comfortable conditions for consumers at intervals between the heating seasons, when the central water heating is disabled.The “air-air” type HP use the ambient air as a low-grade heat source (LGHS). At low air temperatures, transformation ratio μ is about 2 and would rise to 3÷4 at higher air temperatures, which ensures high cost-efficiency of heating systems based on heat pumps. The heating season can generally be divided into two periods. One of the periods is characterized by the highest ambient air temperatures (–5÷8°С). This period is rather long and, in warmer winters, can last for about 4000 hours per heating season, or longer. This is the period, when the heat pump operates efficiently at a transformation ratio above 4.The other period, when the ambient temperature falls below –10÷ –20°С, generally lasts for a small number of hours, which makes about 15÷18% of the total duration of the heating season. At this period, the efficiency of the heat pump would decrease to μ =1.9÷2. Yet, even with such an efficiency, a heat pump delivers twice as much heat as the electric power it consumes.Therefore, in regions with a long period of temperatures within the range of –5÷8°С during a heating season, air heating based on HP can be advantageous compared to water heating.

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 From the Wastewater Treatment Plant to the Turnstiles of Urban Water and District Heating Networks

2020 ◽  
Vol 2 ◽  
Author(s):  
Wolfgang Gruber-Glatzl ◽  
Christoph Brunner ◽  
Sarah Meitz ◽  
Hans Schnitzer
Keyword(s):  
Wastewater Treatment ◽  
Heat Pump ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
District Heating ◽  
Heat Pumps ◽  
Reference Scenario ◽  
Selling Price ◽  
Price Ratio ◽  
Heating Networks

Wastewater treatment plants (WWTP) are among the largest energy consumers in municipalities and cause high operating costs. At the same time, many WWTPs produce biogas and have immense untapped potential for the integration of heat pumps (HP). District heating operators are looking for new possibilities to diversify their heat production portfolio and to provide cheap and clean heat to their customers. In our work, we investigate the case study of the WWTP Gleisdorf (Austria) and propose a combination of biogas utilization and heat pump integration to deliver heat for all internal thermal processes as well as to a 1,000 m heat connection line (HCL) toward the district heating network. The net annual costs of different scenarios were calculated for economic comparison. Negative net annual costs mean net annual savings. The reference scenario (biogas combined heat and power, no HCL, no HP; net annual costs of −51,000 €/year) is compared with three different heat pump integration options (HP-IO). The HP-IOs are considering different hydraulic connections, flow temperatures, and heat exchanger placement. The HP-IO-1 focuses on the low-temperature internal demands, but proves to be too limited to balance out the high cost of the HCL. HP-IO-2 operates at higher temperatures (75°C) leading to the lowest efficiency, but ultimately achieving the lowest net annual costs (−57,700 €/years with a 750 kWth HP). HP-IO-3 uses a serial heating concept trying to take advantage of lower flow temperatures while also delivering heat to the district heating network. At 300–400 kWth this leads to net annual costs of −50,100 €/years. The price ratio of 0.5 (40 €/MWh selling price of heat to 80 €/MWh purchasing price of electricity) are varied to analyze the sensitivity of the results. HPs already play an increasing role in the district heating sector, using sewage water as a heat source. The combined analysis of biogas utilization, HP integration options and the thermal as well as electrical demands of WWTP and district heating networks allow the determination of the most viable option.

scholarly journals District Power-To-Heat/Cool Complemented by Sewage Heat Recovery

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 364 ◽  
Author(s):  
Marcello Aprile ◽  
Rossano Scoccia ◽  
Alice Dénarié ◽  
Pál Kiss ◽  
Marcell Dombrovszky ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Heat Pump ◽  
Heat Recovery ◽  
Renewable Energy Sources ◽  
District Heating ◽  
Heat Pumps ◽  
Economic Feasibility ◽  
Operational Experience ◽  
Operational Parameters ◽  
Heating And Cooling

District heating and cooling (DHC), when combined with waste or renewable energy sources, is an environmentally sound alternative to individual heating and cooling systems in buildings. In this work, the theoretical energy and economic performances of a DHC network complemented by compression heat pump and sewage heat exchanger are assessed through dynamic, year-round energy simulations. The proposed system comprises also a water storage and a PV plant. The study stems from the operational experience on a DHC network in Budapest, in which a new sewage heat recovery system is in place and provided the experimental base for assessing main operational parameters of the sewage heat exchanger, like effectiveness, parasitic energy consumption and impact of cleaning. The energy and economic potential is explored for a commercial district in Italy. It is found that the overall seasonal COP and EER are 3.10 and 3.64, while the seasonal COP and EER of the heat pump alone achieve 3.74 and 4.03, respectively. The economic feasibility is investigated by means of the levelized cost of heating and cooling (LCOHC). With an overall LCOHC between 79.1 and 89.9 €/MWh, the proposed system can be an attractive solution with respect to individual heat pumps.

scholarly journals Temperature level optimization for low-grade thermal networks using the exergy method

2021 ◽  
Vol 2042 (1) ◽  
pp. 012029
Author(s):  
Yolaine Adihou ◽  
Malick Kane ◽  
Julien Ramousse ◽  
Bernard Souyri
Keyword(s):  
Geothermal Energy ◽  
Renewable Energy Sources ◽  
Electricity Consumption ◽  
District Heating ◽  
Heat Pumps ◽  
Energy Sources ◽  
Low Grade ◽  
Temperature Level ◽  
Optimal Network ◽  
Exergy Method

Abstract Low-temperature thermal networks open the field for additional renewable and recovered energy sources to be used. The exploitation of low exergy level resources requires decentralized heat pumps having a significant impact on the network's overall electricity consumption. Thus, a compromise must be found in order to minimize thermal and electrical consumption while integrating a maximum of renewable energy sources. This optimum is governed by the temperature level of the network. This paper aims at determining the optimal network temperature using the exergy criterion. The exergy method is detailed and applied to the multi-source network blueCAD (Fribourg) fed by geothermal energy, and FriCAD, a high temperature district heating network. The optimum temperature decreases as the share of geothermal energy in the production increases. For blueCAD, it ranges from 40 to 55 °C.

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.

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