A technical note investigating the combination boiler market as a proxy for a simple thermal quality of service standard in heat interface units

2019 ◽  
Vol 40 (5) ◽  
pp. 627-637
Author(s):  
Huw Blackwell
Keyword(s):  
Flow Rate ◽  
Thermal Power ◽  
District Heating ◽  
Technical Note ◽  
Hot Water ◽  
Heating Systems ◽  
Domestic Hot Water ◽  
The Uk ◽  
Heating Networks

Heat interface units used in district heating networks provide very similar services to those expected from domestic gas boilers. As heat interface units become more common, it is becoming clear that heat interface units are often oversized. This technical note aims to review and summarise the technical specification of equipment typically available from combination boiler (also known as combi boilers) manufacturers in the UK. This includes thermal outputs and flow rate limitations, particularly those associated with domestic hot water production. It is proposed for use as an equivalent typical minimum domestic hot water flow rate and maximum thermal power benchmark for domestic hot water production by heat interface units, which are utilised in the equivalent role in the communal and district heating market. The aim is to prevent extensive oversizing of heat interface units, thereby reducing capital costs, pipe sizes and improving efficiency on district and communal heating networks. Practical application: This technical note proposes a DHW quality of service standard based on a review of the UK heating system market (specifically the combination boiler market) and water consumption restrictions arising from Building Regulations. This may be used to define an equivalent maximum thermal power and minimum service flow rate when specifying heat interface units used in residential communal heating systems and district heating systems.

scholarly journals District heating and cogeneration in the EU-28: Current situation, potential and proposed energy strategy for its generalisation

2016 ◽  
Vol 3 (2) ◽  
pp. 107
Author(s):  
Enrique Rosales-Asensio ◽  
David Borge-Diez
Keyword(s):  
Power Plants ◽  
Waste Heat ◽  
Thermal Power ◽  
District Heating ◽  
Hot Water ◽  
Energy Strategy ◽  
Horizon 2020 ◽  
Major Player ◽  
Heating Networks ◽  
The Eu

<p class="Textoindependiente21"><span lang="EN-US">Yearly, EU-28 conventional thermal generating plants reject a greater amount of energy than what ultimately is utilised by residential and commercial loads for heating and hot water. If this waste heat were to be used through district heating networks, given a previous energy valorisation, there would be a noticeable decrease in imported fossil fuels for heating. As a consequence, benefits in the form of an energy efficiency increase, an energy security improvement, and a minimisation of emitted greenhouse gases would occur. Given that it is not expected for heat demand to decrease significantly in the medium term, district heating networks show the greatest potential for the development of cogeneration. However, to make this happen, some barriers that are far from being technological but are mostly institutional and financial need to be removed. The purpose of this review is to provide information on the potential of using waste heat from conventional thermal power plants (subsequently converted into cogeneration plants) in district heating networks located in the EU-28. For this, a preliminary assessment is conducted in order to show an estimate of the cost of adopting an energy strategy in which district heating networks are a major player of the energy mix. From this assessment, it is possible to see that even though the energy strategy proposed in this paper, which is based on a dramatic increase in the joint use of district heating networks and cogeneration, is capital-intensive and would require an annual investment of roughly 300 billion euros, its adoption would result in a reduction of yearly fuel expenses in the order of 100 billion euros and a shortening of about 15% of the total final energy consumption, which makes it of paramount interest as an enabler of the legal basis of the “Secure, Clean and Efficient Energy” future enacted by the EU-28 Horizon 2020.</span></p>

scholarly journals Design methodology for combined production and distribution for domestic hot water and space heating

2019 ◽  
Vol 111 ◽  
pp. 01089
Author(s):  
Ivan Verhaert
Keyword(s):  
Distribution Systems ◽  
Production Systems ◽  
District Heating ◽  
Local Heat ◽  
Hot Water ◽  
Space Heating ◽  
Heating Systems ◽  
Domestic Hot Water ◽  
Production And Distribution ◽  
Collective Housing

As local heat demand is reducing due to an increased insulation rate, investing in sustainable heat production becomes less interesting. Nevertheless a substantial demand of heat remains in which the thermal energy needed for the generation of domestic hot water grows relatively in importance. In the last two years standards to size production and distribution systems were revised and methods based on tap patterns were elaborated. Nevertheless, some aspects were not covered yet, e.g. how to deal with decentralized storage and how to use these results and new insights in combined heating systems, taking into account that modifications in standards for both space heating and domestic hot water installations are reducing the oversizing. In this paper, first some critical points of attention due to this evolution are illustrated with a case example. Next it is shown how different rules of thumb often developed by different manufacturers deal with these aspects, but lacking however compatibility with existing standards and/or new insights. Finally, a methodology is proposed and illustrated how to size distribution and production systems for combined heating systems taking into account central and decentralized storage and different kind of end users. The method can be used to size heating systems in collective housing or in district heating networks.

Potential carbon emissions reduction related to the recovery of unutilised waste heat

2021 ◽  
pp. 014362442098627
Author(s):  
Lina Aglén
Keyword(s):  
Carbon Emissions ◽  
Heat Supply ◽  
Waste Heat ◽  
District Heating ◽  
Technical Note ◽  
Building Stock ◽  
Heat Potential ◽  
The Uk ◽  
The Impact ◽  
Heating Networks

The introduction of district heating will have a significant impact on the building services industry, from the architecture of a building to its operation. This technical note investigates a delimited portion of the potential of currently unutilised heat which has the possibility to supply district heating networks in the UK. The UK industrial sector, wastewater treatment facilities and the existing UK waste incineration plants all produce waste heat available in a temperature range suitable for extraction into district heating networks via commercialised techniques broadly used in other countries. This technical note presents a comparative literature review, comparing UK statistics and studies with performance data based on Swedish operational facilities. It finds 51.7TWh of currently unutilised heat could be recovered annually, with a significant associated emission decrease if incorporated into the heat supply of the UK building stock. A quantitative analysis is carried out to compare the identified potential with the current UK heat demand and the potential impact on the UK carbon emissions is estimated. The calculations indicate a reduction of 14% in the required UK total domestic heat supply, despite only including a limited fraction of the available waste heat potential. This technical note serves to highlight and emphasise the large amount of available waste heat potential currently not utilised in the UK. By estimating the impact of waste heat utilisation and incorporation into district heating and heat networks in the UK, the technical note aims to fuel discussion around the further incorporation of waste heat to be utilised in the UK heat sector.

scholarly journals RELaTED Project: New Developments on Ultra-Low Temperature District Heating Networks

Proceedings ◽  
2020 ◽  
Vol 65 (1) ◽  
pp. 25
Author(s):  
Antonio Garrido Marijuan ◽  
Roberto Garay ◽  
Mikel Lumbreras ◽  
Víctor Sánchez ◽  
Olga Macias ◽  
...  
Keyword(s):  
Low Temperature ◽  
High Performance ◽  
Waste Heat ◽  
District Heating ◽  
Hot Water ◽  
Thermal Systems ◽  
Heating Source ◽  
Wide Range ◽  
Thermal Sources ◽  
Heating Networks

District heating networks deliver around 13% of the heating energy in the EU, being considered as a key element of the progressive decarbonization of Europe. The H2020 REnewable Low TEmperature District project (RELaTED) seeks to contribute to the energy decarbonization of these infrastructures through the development and demonstration of the following concepts: reduction in network temperature down to 50 °C, integration of renewable energies and waste heat sources with a novel substation concept, and improvement on building-integrated solar thermal systems. The coupling of renewable thermal sources with ultra-low temperature district heating (DH) allows for a bidirectional energy flow, using the DH as both thermal storage in periods of production surplus and a back-up heating source during consumption peaks. The ultra-low temperature enables the integration of a wide range of energy sources such as waste heat from industry. Furthermore, RELaTED also develops concepts concerning district heating-connected reversible heat pump systems that allow to reach adequate thermal levels for domestic hot water as well as the use of the network for district cooling with high performance. These developments will be demonstrated in four locations: Estonia, Serbia, Denmark, and Spain.

scholarly journals New Deterministic Mathematical Model for Estimating the Useful Energy Output of a Medium-Sized Solar Domestic Hot Water System

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2753
Author(s):  
Miroslaw Zukowski ◽  
Walery Jezierski
Keyword(s):  
Thermal Power ◽  
Optimization Procedure ◽  
Climatic Conditions ◽  
Point Of View ◽  
Hot Water ◽  
Energy Output ◽  
Daily Consumption ◽  
Software Environment ◽  
Optical Efficiency ◽  
Domestic Hot Water

According to the authors of this paper, the mathematical point of view allows us to see what sometimes cannot be seen from the designer’s point of view. The aim of this study was to estimate the influence of the most important parameters (volume of heat storage tanks, daily consumption of domestic hot water, optical efficiency, heat loss coefficient, and total area of a solar collector) on the thermal power output of solar domestic hot water (SDHW) system in European climatic conditions. Three deterministic mathematical models of these relationships for Madrid, Budapest, and Helsinki were created. The database for the development of these models was carried out using computer simulations made in the TRNSYS software environment. The SDHW system located at the Bialystok University of Technology (Poland) was the source of the measurement results used to validate the simulation model. The mathematical optimization procedure showed that the maximum annual useful energy output that can be obtained from 1 m2 of gross collector area is 1303 kWh in the case of Madrid, 918.5 kWh for Budapest, and 768 kWh for Helsinki weather conditions.

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.

Method for Redesign of District Heating Networks within Transition from the 2nd to the 3rd Generation

2014 ◽  
Vol 657 ◽  
pp. 689-693
Author(s):  
Răzvan Corneliu Lefter ◽  
Daniela Popescu ◽  
Alexandrina Untăroiu
Keyword(s):  
District Heating ◽  
Design Stage ◽  
Heating Systems ◽  
Load Duration ◽  
Load Duration Curve ◽  
District Heating Systems ◽  
Consumption Rates ◽  
Heat Loads ◽  
Heating Networks

Important investmentsare made lately in the area of district heating, as a technology capable ofhelping countries to reach sustainability goals. In Romania, European fundswere spent for transition from the 2nd to the 3rdgeneration of district heating systems. The lack of appropriate monitoringsystems in old district heating systems makes optimisation nowadays very difficult,especially because nominal values used in the first design stage areoverestimated. Realistic nominal heat loads are necessary to make goodestimations of hydraulic parameters to be used for redesign. This studyproposes a method that uses the heat load duration curve theory to identify theappropriate nominal heat loads to be used for redesign. Comparison betweenresults obtained by applying the nominal heat loads of each consumer, as theywere established in the first design stage, and the ones identified by theproposed method are analyzed in a case study. The results show that errors arein the +/- 3% band, between the metered heat consumption rates and the proposedrates. The new method can be used for the sizing of pumps and district heatingnetworks after retrofit, in order to get better adjustments of the circulationpumps and increase of the energy efficiency.

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