CHOICE OF ENERGY DATA IN ENVIRONMENTAL ASSESSMENT OF THE BUILT ENVIRONMENT

2003 ◽  
Vol 05 (01) ◽  
pp. 83-97 ◽  
Author(s):  
FREDRIK BURSTRÖM VON MALMBORG ◽  
ANNA FORSBERG
Keyword(s):  
Built Environment ◽  
Heat Production ◽  
Environmental Performance ◽  
Energy Use ◽  
District Heating ◽  
Maintenance Phase ◽  
Heating System ◽  
Electricity Production ◽  
District Heating System ◽  
Electricity Mix

Life cycle oriented methods are increasingly used for environmental assessments (EAs) of the built environment. However, many assumptions are made in such assessments, potentially influencing the results and making the assessment more ambiguous. To increase the reliability of EAs, consequences of the assumptions made have to be better understood. Since energy use in the operation and maintenance phase is an important factor decisive for the overall environmental performance of a building, the purpose of this study is to investigate how the selection of heat and electricity mix affects the assessed environmental performance of buildings. It also aims to suggest how to choose heat and electricity data in EAs of the built environment in general. Applying four different modes of electricity production and two different modes of heat production in a case study of three different buildings with different technical solutions for heat and electricity supply, the study show that choices of heat and electricity mix have significant influence on the final results of the EA. Regarding the choice of heat and electricity mix in an EA of buildings and the built environment, it is argued that both average and marginal data on electricity production should be used in general. As for data on district heat production, it is recommended to use data on the average production in the specific, local district heating system in general. Finally, it is argued that consequences of the assumptions made should be explicitly communicated in the EA report, so as to let the decision-makers rather than the analysts make the evaluation.

scholarly journals Advanced Control of a District Heating System with High Residential Domestic Hot Water Demand

2020 ◽  
Vol 160 ◽  
pp. 01004 ◽  
Author(s):  
Stanislav Chicherin ◽  
Lyazzat Junussova ◽  
Timur Junussov
Keyword(s):  
Energy Demand ◽  
Energy Use ◽  
District Heating ◽  
Heating System ◽  
Primary Energy ◽  
Hot Water ◽  
District Heating System ◽  
Domestic Hot Water ◽  
Extreme Load ◽  
Flow Controller

Proper adjustment of domestic hot water (DHW) load structure can balance energy demand with the supply. Inefficiency in primary energy use prompted Omsk DH company to be a strong proponent of a flow controller at each substation. Here the return temperature is fixed to the lowest possible value and the supply temperature is solved. Thirty-five design scenarios are defined for each load deviation index with equally distributed outdoor temperature ranging from +8 for the start of a heating season towards extreme load at temperature of -26°C. All the calculation results are listed. If a flow controller is installed, the customers might find it suitable to switch to this type of DHW supply. Considering an option with direct hot water extraction as usual and a flow controller installed, the result indicates that the annual heat consumption will be lower once network temperatures during the fall or spring months are higher. The heat load profiles obtained here may be used as input for a simulation of a DH substation, including a heat pump and a tank for thermal energy storage. This design approach offers a quantitative way of sizing temperature levels in each DH system according to the listed methodology and the designer's preference.

Heat Accumulator in Large District Heating Systems: Simulation and Optimisation

2010 ◽  
Author(s):  
Krzysztof Badyda ◽  
Wojciech Bujalski ◽  
Jarosław Milewski ◽  
Michał Warchoł
Keyword(s):  
Heat Production ◽  
District Heating ◽  
Heating System ◽  
Heat Accumulator ◽  
District Heating System ◽  
Heating Systems ◽  
District Heating Systems ◽  
On Line ◽  
Systems Simulation

Heat accumulators in large district heating systems are used to buffer heat production. Their main purpose is to make heat production as independent as possible from district heating system demand. To do this effectively a heat accumulator of appropriate capacity must be selected. In large district heating systems, heat accumulators can be used for equalising production over periods lasting a few hours. Accumulators can be used for optimising electricity and heat production to achieve possible highest income. It may be important in situations where on-line prices change. An optimising algorithm for heat accumulator use is shown and commented. Typical working situations are simulated and results presented.

scholarly journals Some Problems of the Integration of Heat Pump Technology into a System of Combined Heat and Electricity Production

10.14311/212 ◽  
2001 ◽  
Vol 41 (2) ◽  
Author(s):  
G. Böszörményi ◽  
L. Böszörményi
Keyword(s):  
Heat Pump ◽  
District Heating ◽  
Heating System ◽  
Energy Utilization ◽  
Electricity Production ◽  
Geothermal Heat ◽  
District Heating System ◽  
Thermal Output ◽  
Short Period

The closure of a part of the municipal combined heat and power (CHP) plant of Košice city would result in the loss of 200 MW thermal output within a realtively short period of time. The long term development plan for the Košice district heating system concentrates on solving this problem. Taking into account the extremely high (90 %) dependence of Slovakia on imported energy sources and the desirability of reducing the emission of pollutantst the alternative of supplying of 100 MW thermal output from geothermal sources is attractive. However the indices of economic efficiency for this alternative are unsatisfactory. Cogeneration of electricity and heat in a CHP plant, the most efficient way of supplying heat to Košice at the present time. If as planned, geothermal heat is fed directly into the district heating network the efficiency would be greatly reduced. An excellent solution of this problem would be a new conception, preferring the utilization of geothermal heat in support of a combined electricity and heat production process. The efficiency of geothermal energy utilization could be increased through a special heat pump. This paper deals with several aspects of the design of a heat pump to be integrated into the system of the CHP plant.

scholarly journals Active Management of Heat Customers Towards Lower District Heating Return Water Temperature

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1863
Author(s):  
Tommy Rosén ◽  
Louise Ödlund
Keyword(s):  
Energy Efficiency ◽  
Water Temperature ◽  
District Heating ◽  
Heating System ◽  
Active Management ◽  
Electricity Production ◽  
Low Grade ◽  
Efficiency Gains ◽  
District Heating System ◽  
Return Water

The traditional way of managing the supply and return water temperatures in a district heating system (DHS) is by controlling the supply water temperature. The return water temperature then becomes a passive result that reflects the overall energy efficiency of the DHS. A DHS with many poorly functioning district heating centrals will create a high return water temperature, and the energy efficiency of the DHS will be affected negatively in several ways (e.g., lower efficiency of the flue gas condenser, higher heat losses in pipes, and lower electricity production for a DHS with combined heat and power (CHP)). With a strategic introduction of low-grade heat customers, the return water temperature can be lowered and, to some extent, controlled. With the heat customers connected in parallel, which is the traditional setup, return water temperatures can only be lowered at the same rate as the heat customers are improved. The active management of some customers can lower the return water temperatures faster and, in the long run, lead to better controlled return water temperatures. Active management is defined here as an adjustment of a domestic heating system in order to improve DHS efficiency without affecting the heating service for the individual building. The opposite can be described as passive management, where heat customers are connected to the DHS in a standardized manner, without taking the overall DHS efficiency into consideration. The case study in this article shows possible efficiency gains for the examined DHS at around 7%. Looking at fuel use, there is a large reduction for oil, with 10–30% reduction depending on the case in question, while the reduction is shown to be largest for the case with the lowest return water temperature. The results also show that efficiency gains will increase electricity production by about 1–3%, and that greenhouse gas (GHG) emissions are reduced by 4–20%.

Heat Recovery Enhancement and Operational Issues of a 200 kWe Fuel Cell Cogeneration Plant

1999 ◽  
Author(s):  
Erika Söderlund ◽  
Andrew R. Martin ◽  
Per Alvfors ◽  
Jonas Forsman ◽  
Laszlo Sarközi
Keyword(s):  
Fuel Cell ◽  
Heat Production ◽  
Heat Recovery ◽  
District Heating ◽  
Original System ◽  
Heating System ◽  
Cogeneration Plant ◽  
District Heating System ◽  
Air Preheater ◽  
Vapor Cloud

Abstract This study presents some of the experiences gained during a two year operational period of a decentralized fuel cell cogeneration plant installed in southern Sweden. Various modifications to the system are described, most notably a plume eliminator for the reduction of an undesirable vapor cloud emitted by the original system. Aside from vapor cloud elimination, the plume eliminator allows for more efficient plant operation, as a larger fraction of the system cooling requirements can be shifted to the district heating system. In-field measurements show a 17 to 26% increase in district heat production with use of the plume eliminator, depending upon the season of operation (winter or summer). The study also presents two options for added heat recovery, which are employed in conjunction with the plume eliminator: an air preheater module; and an air preheater/humidifier module. Calculations show that air preheating has a small but measurable impact on heat recovery (an additional 8% gain), while combined air preheating and humidification allows for nearly a 50% increase in district heat production.

scholarly journals Climate Index for District Heating System

2020 ◽  
Vol 24 (1) ◽  
pp. 406-418
Author(s):  
Ieva Pakere ◽  
Dace Lauka ◽  
Kristiāna Dolge ◽  
Valdis Vitolins ◽  
Ilze Polikarpova ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Natural Gas ◽  
Environmental Impact ◽  
Heat Production ◽  
System Performance ◽  
Energy Supply ◽  
District Heating ◽  
Heating System ◽  
Climate Index ◽  
District Heating System

AbstractDistrict heating (DH) has been highlighted as an important part in future carbon neutral energy supply. However, the performance of different DH systems varies a lot and the existing regulations do not always motivate DH companies to move toward more sustainable heat production. Therefore, this article presents novel methodology for Climate index determination which can be further used for the comparison of DH systems. The Climate index includes seven different indicators which show DH system performance according to energy efficiency, sustainability and environmental impact dimensions. The methodology is applied for 20 different DH systems operating in Latvia. The results show that the performance of 5 natural gas-based DH systems is below the determined climate benchmark.

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