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.

Study on the Comprehensive Program of Heat Pump Technology Recycling Thermal Power Plants Circulating Water Heat

2013 ◽  
Vol 313-314 ◽  
pp. 759-762
Author(s):  
Yun Feng Ma ◽  
Yan Xiang Liu ◽  
Tao Ji
Keyword(s):  
Heat Pump ◽  
Power Plants ◽  
Waste Heat ◽  
Thermal Power ◽  
Heating System ◽  
Hot Water ◽  
Thermal Power Plants ◽  
Domestic Hot Water ◽  
Circulating Water ◽  
Central Heating

In order to fully recycle power plant’s circulatingwater heat, improve the thermal efficiency and protect the environment, thispaper designs the comprehensive scheme of heat pumptechnology recycling power plant’s circulating water heat, including theboiler mae-up water pre-heating system, the central heating circulatingsystem and the domestic hot water circulating system, which not only run at thesame time but also function independently. Even in non-heating seasons,the waste heat of circulating water can be utilized fully. It is worthmentioning that this paper puts forward to install climate compensationdevice in the central heating system, which can perform intelligent district timesharing control to meet different users’ needs.

scholarly journals Performance analysis of glazed PVT collectors for multifamily building

2020 ◽  
Vol 172 ◽  
pp. 12003
Author(s):  
Nikola Pokorny ◽  
Tomas Matuska
Keyword(s):  
Mathematical Model ◽  
Performance Analysis ◽  
Potential Application ◽  
Simulation Analysis ◽  
Climatic Conditions ◽  
Building Envelope ◽  
Hot Water ◽  
Photovoltaic Panels ◽  
Domestic Hot Water ◽  
Solar Thermal Collectors

The paper deals with performance analysis of potential application of glazed photovoltaic-thermal collector for domestic hot water preparation for multifamily building in European climatic conditions. Two different solutions are studied, glazed photovoltaic-thermal collectors integrated in the building envelope and glazed photovoltaic-thermal collectors fixed on the roof of the building. Moreover, the paper presents a comparison with conventional side by side installation of solar thermal collectors and photovoltaic panels to show the benefit of photovoltaic-thermal collectors. Simulation analysis has been done in TRNSYS with use of developed and validated mathematical model of glazed photovoltaic-thermal collector.

Characterization of a Thermosyphon Heat Exchanger for Solar Domestic Hot Water Systems

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Cynthia A. Cruickshank ◽  
Stephen J. Harrison
Keyword(s):  
Heat Exchanger ◽  
Test Procedure ◽  
Water Systems ◽  
Climatic Conditions ◽  
Hot Water ◽  
Test Method ◽  
Domestic Hot Water ◽  
Operational Conditions ◽  
Flow And Heat Transfer

This paper presents a simplified test method that was developed to allow preconfigured solar domestic hot water systems that use natural convection/thermosyphon heat exchangers to be characterized. The results of this test method produce performance coefficients for simple empirical expressions that describe the fluid flow and heat transfer in the heat-exchange loop. These empirically derived coefficients can be used as an input to a general simulation routine that allows overall system performance to be determined for various loads and climatic conditions. To illustrate the test procedure, results are presented for a typical heat exchanger under a range of operational conditions.

scholarly journals Monthly model of hot water consumption

2019 ◽  
Vol 100 ◽  
pp. 00007
Author(s):  
Agnieszka Chmielewska
Keyword(s):  
Statistical Analysis ◽  
Water Consumption ◽  
Strong Correlation ◽  
Hot Water ◽  
Daily Consumption ◽  
Domestic Hot Water ◽  
Apartment Buildings ◽  
Holiday Period ◽  
Housing Structure

The article presents a statistical analysis of the monthly consumption of hot water in apartment buildings. On this basis, a monthly model of hot water consumption in multi-family buildings was proposed. This model consists of two sub models: model of average daily consumption of domestic hot water and a model describing changes in consumption of hot water in individual months of the year. To construct the model of average daily consumption of hot water, data on the consumption of hot water was used out of 16 multi-family buildings from the period of two years. The data was supplemented with information on the housing structure in the building. The study of changes in hot water consumption in the following months was based on data obtained from 30 buildings. Statistical analysis showed a strong correlation between the monthly consumption of hot water, the outside temperature and holiday period.

scholarly journals Design and Analysis of the Domestic Micro-Cogeneration Potential for an ORC System Adapted to a Solar Domestic Hot Water System

Entropy ◽  
2019 ◽  
Vol 21 (9) ◽  
pp. 911 ◽  
Author(s):  
Daniel Leal-Chavez ◽  
Ricardo Beltran-Chacon ◽  
Paola Cardenas-Terrazas ◽  
Saúl Islas ◽  
Nicolás Velázquez
Keyword(s):  
Solar Collector ◽  
Electric Energy ◽  
Water System ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Point Of View ◽  
Hot Water ◽  
Working Fluid ◽  
Condensation Temperature ◽  
Domestic Hot Water

This paper proposes the configuration of an Organic Rankine Cycle (ORC) coupled to a solar domestic hot water system (SDHWS) with the purpose of analyzing the cogeneration capacity of the system. A simulation of the SDHWS was conducted at different temperatures, observing its performance to determine the amounts of useable heat generated by the solar collector; thus, from an energy balance point of view, the amount of heat that may be used by the ORC could be determined. The working fluid that would be suitable for the temperatures and pressures in the system was selected. The best fluid for the given conditions of superheated vapor at 120 °C and 604 kPa and a condensation temperature of 60 °C and 115 kPa was acetone. The main parameters for the expander thermodynamic design that may be used by the ORC were obtained, with the possibility of generating 443 kWh of annual electric energy with 6.65% global efficiency of solar to electric power, or an overall efficiency of the cogeneration system of 56.35% with a solar collector of 2.84 m2.

scholarly journals Performance Assessment of Example PVT-Systems

2020 ◽  
Author(s):  
Maike Schubert ◽  
Daniel Zenhäusern
Keyword(s):  
Heat Source ◽  
Heat Pump ◽  
Performance Indicators ◽  
Control Strategies ◽  
Climatic Conditions ◽  
Hot Water ◽  
Water Production ◽  
Swimming Pools ◽  
Domestic Hot Water ◽  
Financial Perspective

The performance of 26 PVT-Systems was analysed and compared in IEA-SHC Task 60. The systems are located in countries with different climatic conditions. The applications range from direct domestic hot water production and heating of public swimming pools to heat pump systems with PVT as the main heat source of the heat pump. The Key Performance Indicators (KPIs) determined for the different PVT solutions give the possibility to compare the systems despite their diversity. The goal was to show the potential of PVT collectors in different fields of application. The results show that the integration of PVT collectors in different kinds of well-dimensioned systems leads to competitive solutions, both from an energy and a financial perspective. Additionally the answers to a survey about control strategies for PVT systems, showing some main problems and possible solutions, are summarised.

scholarly journals Experimental Assessment of a Multi-Variable Control Strategy of a Micro-Cogeneration Solar-ORC Plant for Domestic Application

2021 ◽  
Vol 312 ◽  
pp. 08006
Author(s):  
Diego Vittorini ◽  
Fabio Fatigati ◽  
Davide Di Battista ◽  
Marco Di Bartolomeo ◽  
Roberto Carapellucci
Keyword(s):  
High Temperature ◽  
Flat Plate ◽  
Thermal Power ◽  
Energy Performance ◽  
Hot Water ◽  
Small Scale ◽  
Domestic Hot Water ◽  
Wide Range ◽  
Electrical Generation ◽  
Operating Points

Suitability to off-design operation, applicability to combined thermal and electrical generation in a wide range of low temperatures and pressures and compliance with safety and environmental limitations qualify small-scale Organic Rankine Cycle plants as a viable option for combined heat and power generation in the residential sector. As the plants scale down, the electric and thermal output maximization has to account for issues, spanning from high pump power absorption, compared to the electric output of the plant, to intrinsically low plant permeability induced by the expander, to the intermittent availability of thermal power, affected by the heat demand for domestic hot water (DHW) production. The present paper accounts for a flat-plate solar thermal collector array, bottomed by an ORC unit featuring a sliding vane expander and pump and flat-plate heat exchangers. A high-temperature buffer vessel stores artificially heated water – electric heaters, simulating the solar collector - and feeds either the hot water line for domestic use or the ORC evaporator, depending on the instantaneous demand (i.e., domestic hot water or electric power), the temperature conditions inside the tank and the stored mass availability. A low-temperature receiver acts like the heat sink of the ORC unit and harvests the residual thermal power, downstream the expander: a dedicated control, modelled to properly modulate the mass addition/subtraction to this storage unit allows to restore the operating points of the cycle and to limit the incidence of off-design operation, via real-time adjustment of the cycle operating parameters. Indeed, the possibility of continuous ORC generation depends on (i) the nature of the demand and (ii) the amount of hot water withdrawn from the high-temperature buffer vessel. The time-to-temperature for the mass stored inside the buffer affects the amount of ORC unit activations and eventually the maximum attainable generation of electric energy. The plant energy performance is experimentally assessed, and various characteristic operating points are mapped, based on test runs carried out on a real-scale ORC pilot unit.

scholarly journals Analysis of the Advisability of Using Solar Collectors in a Single-Family House in Poland and Spain

Proceedings ◽  
2020 ◽  
Vol 51 (1) ◽  
pp. 9
Author(s):  
Bernadetta Wądołowska ◽  
Dorota Anna Krawczyk
Keyword(s):  
Thermal Power ◽  
Climatic Conditions ◽  
Heat Losses ◽  
Hot Water ◽  
Operating Costs ◽  
Solar Collectors ◽  
Single Family ◽  
Fuel Prices ◽  
Heating Installation ◽  
Family House

In this paper we show the advisability of usage of solar collectors for domestic hot water (DHW) preparation in buildings located in two countries: Poland and Spain. The analysis was conducted for a single-family house with horizontal roof. During the calculations we took into account factors depending on the building location such as national rules, climatic conditions, cost of system installation, and fuel and electricity prices. Based on the total design heat losses and demand for DHW, the demand for usable energy for heating the buildings and DHW preparation was calculated. A gas boiler was selected as the heat source of the building, and solar collectors (flat-plate and vacuum pipe) were chosen as the source of DHW preparation. Installation investment costs and annual operating costs have been stamped. Calculations show that for buildings located in Spain, heat losses were 36.5% lower and the demand for thermal power for DHW was 59.5% lower than for buildings located in Poland. Annual operating costs of the heating installation for both buildings were at similar levels, due to high fuel prices in Spain, while the operating costs of DHW installations were 28.2% higher for locations in Poland. The results show that the use of solar collectors in Poland is economically justified.

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.

OPTIMAL HIGH PRESSURE CORRELATION FOR R744 DIRECT EXPANSION SOLAR ASSISTED HEAT PUMP FOR DOMESTIC HOT WATER

2018 ◽  
Author(s):  
Willian Moreira Duarte ◽  
Tiago de Freitas Paulino ◽  
Sabrina Nogueira Rabelo ◽  
Luiz Machado ◽  
Antônio Maia
Keyword(s):  
High Pressure ◽  
Heat Pump ◽  
Hot Water ◽  
Direct Expansion ◽  
Domestic Hot Water
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