scholarly journals Numerical assessment of a gas-fired condensing boiler model for residential buildings application

2021 ◽  
Vol 2116 (1) ◽  
pp. 012016
Author(s):  
K Simic ◽  
I T’Jollyn ◽  
W Faes ◽  
J Borrajo Bastero ◽  
J Laverge ◽  
...  
Keyword(s):  
Natural Gas ◽  
Input Data ◽  
Numerical Models ◽  
Residential Buildings ◽  
Software Tool ◽  
Heat Transfer Process ◽  
Hot Water ◽  
Dew Point ◽  
The European Union ◽  
Combustion Gases

Abstract According to the official statistical reports, gas-fired boiler units still remain to be one of the main equipment types for meeting the space heating and daily hot water demand of the residential dwellings across the European Union. Due to the prevalence of the natural gas grid and performance stability, gas-fired boilers are considered to remain as one of the standard energy sources. On the other hand, even though gas-fired water heating technology is a well-known concept, existing numerical models found in the literature are often case-specific with poor reusability mostly reflected in fitted efficiencies. Algorithms behind these models usually require the input of large amount of hardly attainable design characteristics of the units. In this paper, a modelling method for acquiring the performance of a heating gas-fired condensing boiler unit will be shown. The model is based on the limited input data available in the official characteristics of the units issued by the relevant manufacturers. The simulations are programmed by using the programming language Modelica and the software tool Dymola. The model is based on the fixed natural gas intake which combusts into a stable mixture of the combustion gases that further heat the circulating water. During the heat transfer process inside the condensing boilers there is a possibility for condensate formation out of the water vapour of the combustion gases which increases the efficiency of the unit. The formation of condensate, however, is depending on the return water temperature of the unit which has to be lower than the dew point temperature of the combustion gasses. The goal of this research is to determine how accurate can performance indicators of gas-fired boilers be attained with the use of a limited amount of available input data together with clearly defined assumptions that follow the modelling methodology.

Cost and environmental performance of forced air and hot water heating systems in post-Soviet countries

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Begmyrat Kulmedov ◽  
Serdar Durdyev
Keyword(s):  
Natural Gas ◽  
Environmental Performance ◽  
Residential Buildings ◽  
Electricity Consumption ◽  
Cost Effective ◽  
Hot Water ◽  
Design Stage ◽  
High Price ◽  
Content Type ◽  
Heating Systems

PurposeThe aim of the present study is to assess the selected heating systems (furnace and boiler) commonly used in the dwellings of seven post-USSR (the Union of Soviet Socialist Republics) countries. The systems were assessed in terms of their cost and environmental performance, with natural gas and electricity used as the main source of energy.Design/methodology/approachThe cost-effectiveness and environmental performance of the selected heating systems that have been commonly used in the selected post-USSR countries was assessed. Current energy (natural gas and electricity) prices that are applied in those countries were used.FindingsResults show that the furnace is the cheapest option, while natural gas is the cheapest source of energy, despite its high price in Tajikistan and Kyrgyzstan. Both heating systems could be considered eco-friendly options, although their efficiencies need to be considered at the design stage. Turkmenistan, Uzbekistan and Kazakhstan, which are the top natural gas producers, offer natural gas for the selected heating systems as both cost-effective and eco-friendly options.Practical implicationsA considerable reduction in electricity consumption and less harm to our environment can be achieved through the systems used in residential buildings in the region.Originality/valueThe outcomes of the present study offer value (in terms of cost-effective and eco-friendly options) for the end-users in the region.

scholarly journals THE MODEL FOR POWER EFFICIENCY ASSESSMENT OF CONDENSATION HEATING INSTALLATIONS

2017 ◽  
Vol 9 (3) ◽  
Author(s):  
D. Kovalchuk ◽  
A. Mazur ◽  
S. Hudz
Keyword(s):  
Heat Pump ◽  
Power Efficiency ◽  
Computer Experiments ◽  
Weather Conditions ◽  
Heating System ◽  
Hot Water ◽  
Dew Point ◽  
Heating Season ◽  
Combustion Gases ◽  
Overall Performance

The main part of heating systems and domestic hot water systems are based on the natural gas boilers. Forincreasing the overall performance of such heating system the condensation gas boilers was developed and are used. Howevereven such type of boilers don't use all energy which is released from a fuel combustion. The main factors influencing thelowering of overall performance of condensation gas boilers in case of operation in real conditions are considered. Thestructure of the developed mathematical model allowing estimating the overall performance of condensation gas boilers(CGB) in the conditions of real operation is considered. Performace evaluation computer experiments of such CGB during aheating season for real weather conditions of two regions of Ukraine was made. Graphic dependences of temperatureconditions and heating system effectiveness change throughout a heating season are given. It was proved that normal CGBdoes not completely use all calorific value of fuel, thus, it isn't effective. It was also proved that the efficiency of such boilerssignificantly changes during a heating season depending on weather conditions and doesn't reach the greatest possible value.The possibility of increasing the efficiency of CGB due to hydraulic division of heating and condensation sections and use ofthe vapor-compression heat pump for deeper cooling of combustion gases and removing of the highest possible amount ofthermal energy from them are considered. The scheme of heat pump connection to the heating system with a convenient gasboiler and the separate condensation economizer allowing to cool combustion gases deeply below a dew point and to warm upthe return heat carrier before a boiler input is provided. The technological diagram of the year-round use of the heat pump forhot water heating after the end of heating season, without gas use is offered.

Baseline, Exhaust-Fired, and Combined Operation of Desiccant Dehumidification Unit

2004 ◽  
Author(s):  
Andrei Yu. Petrov ◽  
Abdolreza Zaltash ◽  
Edward A. Vineyard ◽  
Solomon D. Labinov ◽  
D. Tom Rizy ◽  
...  
Keyword(s):  
Natural Gas ◽  
Power Output ◽  
Waste Heat ◽  
Hot Water ◽  
Dew Point ◽  
Low Grade ◽  
Oak Ridge ◽  
Gas Burner ◽  
The Impact ◽  
Combined Mode

The performance of a commercially available direct-fired desiccant dehumidification unit (DFDD) has been studied as part of a microturbine generator (MTG)-based Integrated Energy System (IES) at Oak Ridge National Laboratory (ORNL). The IES includes a second-generation air-to-water heat recovery unit (HRU) for the MTG. The focus of these tests was to study the performance of a DFDD in baseline (direct-fired with its natural gas burner) mode and to compare it with a DFDD performance in the exhaust-fired and combined modes as part of the ORNL IES, when waste heat received from the MTG was used for desiccant regeneration. The baseline tests were performed with regeneration air heated by a natural gas burner (direct-fired). The testing of the waste-heat, or exhaust-fired DFDD as part of IES involved using the exhaust gas from the HRU for regeneration air in the DFDD after hot water production in the HRU. Hot water from the HRU was used to produce chilled water in an indirect-fired (water fired) absorption chiller. The combined DFDD was the combination of natural gas burner and exhaust-fired testing. The study investigated the impact of varying the process and regeneration conditions on the latent capacity (LC) and latent coefficient of performance (LCOP) of the DFDD, as well as overall IES efficiency. The performance tests show that LC increases with increasing dew point (humidity ratio) of the process air or the increased amount of waste heat associated with increased MTG power output. In addition, baseline LC was found to be three times higher than the LC in the exhaust-fired mode of operation. LCOP in baseline operation is also almost three times higher than that obtained in the exhaust-fired mode (55.4% compared to 19%). But, at the same time, addition of the DFDD to the IES with the MTG at maximum power output increases the overall IES efficiency by 4–5%. Results of the combined tests performed at a reduced MTG power output of 15 kW (51,182 Btu/h) and their comparison with the baseline and exhaust-fired tests show that activation of the DFDD gas burner during exhaust-fired tests increases the LC over the baseline value from 91,514.9 Btu/h (25.8 kW) to 101,835.8 Btu/h (29.8 kW). The LCOP during the combined mode is less than the “baseline” LCOP, because in addition to gas input, the low-grade MTG/HRU exhaust heat input to the DFDD are also being considered. The overall IES efficiency during the combined mode is approximately 8% higher than without the DFDD integrated into the IES.

scholarly journals Integration of Micro-Cogeneration Units and Electric Storages into a Micro-Scale Residential Solar District Heating System Operating with a Seasonal Thermal Storage

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5456
Author(s):  
Antonio Rosato ◽  
Antonio Ciervo ◽  
Giovanni Ciampi ◽  
Michelangelo Scorpio ◽  
Sergio Sibilio
Keyword(s):  
Natural Gas ◽  
Residential Buildings ◽  
Electric Energy ◽  
District Heating ◽  
Thermal Storage ◽  
Hot Water ◽  
District Heating System ◽  
Domestic Hot Water ◽  
Micro Scale ◽  
Gas Fueled

A micro-scale district heating network based on the operation of solar thermal collectors coupled to a long-term borehole thermal storage is modeled, simulated and investigated over a period of five years. The plant is devoted to covering the domestic hot water and space heating demands of a district composed of six typical residential buildings located in Naples (southern Italy). Three alternative natural gas-fueled back-up auxiliary systems (condensing boiler and two different technologies of micro-cogeneration) aiming at balancing the solar energy intermittency are investigated. The utilization of electric storages in combination with the cogeneration systems is also considered with the aim of improving the self-consumption of cogenerated electric energy; heat recovery from the distribution circuit is also evaluated to pre-heat the mains water for domestic hot water production. The performances of the proposed plant schemes are contrasted with those of a typical Italian decentralized heating plant (based on the utilization of natural gas-fueled non-condensing boilers). The comparison highlighted that the proposed configurations can decrease the primary energy consumption (up to 11.3%), the equivalent emissions of carbon dioxide (up to 11.3%), and the operation costs (up to 14.3%), together with an acceptable simple pay-back period (about 4.4 years).

scholarly journals Numerical assessment of self-sufficiency of residential buildings in Belgium by using heat pumps, photovoltaic panels and energy storages

2021 ◽  
Vol 2069 (1) ◽  
pp. 012115
Author(s):  
Katarina Simic ◽  
Klaas Thiers ◽  
Hugo Montyne ◽  
Jan Desmet ◽  
Michel De Paepe
Keyword(s):  
Energy Storage ◽  
Energy Demand ◽  
Energy Use ◽  
Numerical Models ◽  
Residential Buildings ◽  
Energy Performance ◽  
Hot Water ◽  
The Self ◽  
Space Heating ◽  
Self Sufficiency

Abstract Residential buildings claim a significant share of the total energy use worldwide. In order to have more realistic energy performance predictions, increased attention is paid to the analysis of the building’s energy use through comprehensive, transient detailed numerical simulations. In this article, the self-consumption and self-sufficiency values of three detached residential buildings are assessed through numerical models made in the programming language Modelica and software tool Dymola. The three buildings have the same structure and different space heating energy demands of 15 kWh/m2year, 30 kWh/m2year and 45 kWh/m2year. The energy use of the buildings coincides with the occupancy profile where domestic hot water use dominates over the space heating demand provided by an air to water heat pump. The discrepancy between renewable energy production and energy consumption is mitigated by means of thermal load shifting and electrical energy storage. In this research, the self-consumption and self-sufficiency of the studied buildings have been analysed as a function of the economically favourable energy storage sizing. For the use of an electrical battery with the installed capacity of 2.5 kWh and thermal energy storage of 250 l, the self-sufficiency results to be 40%, 38.5% and 37% for the three buildings respectively at the specific simulated energy demand conditions.

scholarly journals The comparison of calculation methods of gas demand in the installation with combi boilers

2018 ◽  
Vol 44 ◽  
pp. 00058
Author(s):  
Andrzej Jedlikowski ◽  
Sebastian Englart
Keyword(s):  
Natural Gas ◽  
Residential Buildings ◽  
Hot Water ◽  
Calculation Methods ◽  
Water Heaters ◽  
Single Function ◽  
Gas Consumption ◽  
Natural Gas Demand ◽  
Reliable Methods ◽  
Selection Of

Combi boilers offer an economic alternative to individual single function gas boilers and instantaneous water heaters. These gas appliances allow for producing thermal energy for two heating purposes (space heating and hot water preparation). For this reason these compact and highly efficient devices are becoming increasingly popular in many residential buildings. The application of such heating systems often requires an adequate approach for determining the natural gas demand. The literature indicates several methods for this purpose, which often differ significantly. Differences in calculated results seem to be the main problem with these methods. Unfortunately, the selection of the above-mentioned gas appliances always causes overestimation of natural gas demand. This is mainly due to the fact that many calculation methods contain incorrect gas demand coefficients. Therefore, this paper presents various methods for estimating gas consumption for multi-family buildings. It provides discussion and analysis of various calculation methods for residential buildings equipped with two types of gas appliance. The performed analysis made it possible to indicate the most reliable methods of gas demand calculation.

scholarly journals Development of Standardized Domestic Hot Water Event Schedules for Residential Buildings

2007 ◽  
Author(s):  
Robert Hendron ◽  
Jay Burch
Keyword(s):  
Energy Use ◽  
Energy Savings ◽  
Residential Buildings ◽  
Probability Distributions ◽  
Software Tool ◽  
Past Research ◽  
Water Systems ◽  
Hot Water ◽  
Domestic Hot Water ◽  
High Level

The Building America Research Benchmark is a standard house definition created as a point of reference for tracking progress toward multi-year energy savings targets. As part of its development, the National Renewable Energy Laboratory (NREL) has established a set of domestic hot water events to be used in conjunction with sub-hourly analysis of advanced hot water systems. In certain applications (including analysis of recirculation loops, distribution losses, tankless gas water heaters, and solar hot water systems with load-side heat exchangers) energy use can be strongly affected by event flow rate, duration, frequency, clustering, and time of occurrence. High-level constraints on mains temperature and average daily hot water use, along with detailed event characteristics derived from past research and a software tool developed by Kassel University in Germany, were used to generate hot water events over one year for houses of different sizes in various locations. The events were established in 6-min increments for showers, baths, sinks, clothes washers, and dishwashers. Flow rates and times of occurrence varied randomly based on specified probability distributions. The final event schedules reflected the same daily variability as an actual household, thereby providing more realism to energy simulations involving advanced water heating systems.

scholarly journals Real Domestic Hot Water Consumption in Residential Buildings and Its Impact on Buildings’ Energy Performance—Case Study in Poland

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5010
Author(s):  
Katarzyna Ratajczak ◽  
Katarzyna Michalak ◽  
Michał Narojczyk ◽  
Łukasz Amanowicz
Keyword(s):  
Energy Consumption ◽  
Natural Gas ◽  
Water Consumption ◽  
Residential Buildings ◽  
Energy Performance ◽  
Primary Energy ◽  
Hot Water ◽  
Domestic Hot Water ◽  
Total Energy Balance ◽  
Consumption Rates

A building’s energy consumption is assessed considering the energy required for heating, cooling, lighting, and domestic hot water (DHW). Methodologies used to calculate energy certificates in European Union countries consider hot water consumption rates per person or per heated (floor) area, giving wide-ranging values (35–88 dm3/person/day). Using extreme parameters, it is possible to obtain a primary energy index that meets the legal requirements, although unrealistically large proportions of domestic hot water use relative to the total energy balance of the building may marginalize the influence of other components, such as fluctuations in heating, ventilation, or lighting. In the current work, the DHW consumption of three residential buildings was measured to verify the energy consumption for hot water preparation. Investigations were conducted based on the consumption of natural gas for DHW preparation. Experimentally obtained water consumption rates were determined per m2 of a dwelling and per person living in the building. The calculated indicators (0.85 ± 0.005 dm3/m2/day and 27.4 ± 1.4 dm3/person/day) were lower than those used for energy certifications of buildings. The experimentally obtained indicators were used in further theoretical energy assessments of six residential buildings. By adopting the designated indicators, the analyzed buildings met the legally required primary energy value (<70 kWh/m2/year) when using natural gas as a heat source. Applying more realistic DHW consumption values resulted in more accurate energy certifications.

scholarly journals Analysis of the Methodology to Obtain Several Key Indicators Performance (KIP), by Energy Retrofitting of the Actual Building to the District Heating Fuelled by Biomass, Focusing on nZEB Goal: Case of Study

Energies ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 93 ◽  
Author(s):  
Rosaura Castrillón Mendoza ◽  
Javier Rey Hernández ◽  
Eloy Velasco Gómez ◽  
Julio San José Alonso ◽  
Francisco Rey Martínez
Keyword(s):  
Energy Efficiency ◽  
Natural Gas ◽  
Energy Management ◽  
District Heating ◽  
Heating System ◽  
Energy System ◽  
Hot Water ◽  
The European Union ◽  
District Heating System ◽  
The University

In order to achieve the objectives of the European 20/20/20 strategy, and to obtain a greater energy efficiency, integration of renewable energies and the reduction of carbon emissions, a District Heating (DH) system has been designed by the University of Valladolid (UVa), Spain, one of the most important DH fed by biomass fuel in Spain, supplying heating and domestic hot water (DHW) to 31 buildings in Valladolid, the majority of them, educational buildings on the University Campus. The aims of this paper were to study the change from an energy system fueled by natural gas to District Heating by biomass in a building on the campus of the University of Valladolid—the School of Engineering (EII)—studying its consumption from its connection to the District Heating system. An energy management methodology such as ISO 50001 is carried out, applied to efficiency systems in buildings, thus establishing new criteria of sustainability and economic value. In this paper, energy management will also be analyzed in accordance with the proposed tools of an Energy Management System (EMS) applied to the EII building, through the measurement of energy parameters, calculation of thermal consumption, thermal energy savings as a result of the change from system to District Heating by biomass, economic savings, reduction of environmental impact and indicators of thermal efficiency I100 and CUSUM indicator. Finally, the primary renewable and non-renewable energy efficiency indicators for the new District Heating system will be determined. The concept of the near Zero Energy Buildings is defined in the European Union (EU) in order to analyze an approach to an nZEB which results from replacing the natural gas heating system by a biomass District Heating system.

Research of pressure influence in the gas supply system on the energy consuption level of gas devices

2019 ◽  
Vol 6 (2) ◽  
pp. 56-63
Author(s):  
L. D. Pylypiv ◽  
І. І. Maslanych
Keyword(s):  
Natural Gas ◽  
Residential Buildings ◽  
Supply System ◽  
Normal Operation ◽  
Gas Combustion ◽  
Efficient Operation ◽  
Gas Consumption ◽  
Natural Gas Combustion ◽  
Gas Supply

There are investigated the influence of operating pressures in the gas supply system on the level of such energy indicators as efficiency, gas flow and gas overrun by gas equipment in residential buildings. There is established a relationship between the values of operating pressures in the gas supply system and the gas consumption level of household appliances. The causes of insufficient pressure in the gas networks of settlements are analyzed in the article. There is also developed an algorithm for calculating the change in the efficiency of gas appliances depending on the operational parameters of the gas network. It has been found that the most efficient operation of gas appliances is observed at an overpressure at the inlet of gas appliances of about 1200 Pa.To ensure the required quality of natural gas combustion among consumers and minimize gas consumption there are justified the following measures in the article: coordinating a domestic regulatory framework for assessing the quality of natural gas with international norms and standards; improving the preparation of gas coming from local wells before supplying it to gas distribution networks; auditing low pressure gas pipelines and reconstructing areas affected by corrosion; ensuring standard gas pressure in the network for the normal operation of domestic gas appliances; stating quality indicators of natural gas combustion by gas sales organizations.

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