scholarly journals Mathematical Modelling and Operation Simulation of the Indirect Connection Scheme of the Heating Installation and of the Consumption Hot Water Preparation in an Accumulating Stage

2021 ◽  
Vol 1203 (2) ◽  
pp. 022077
Author(s):  
Danut Tokar ◽  
Sanda Mirela Toropoc ◽  
Rodica Frunzulica ◽  
Petrica Toma ◽  
Adriana Tokar
Keyword(s):  
Mathematical Model ◽  
Heat Exchanger ◽  
Hot Water ◽  
Domestic Hot Water ◽  
Indirect Connection ◽  
Model And Simulation ◽  
Module Type ◽  
Quantity Of Heat ◽  
The Mathematical Model ◽  
Residential Consumers

Abstract This paper presents the mathematical model and simulation of a thermal system for heating and supplying hot water to industrial or residential consumers consisting of a heat exchanger on the heating circuit and a heat exchanger provided with an accumulation tank on the domestic hot water circuit, this scheme is generally adopted in the industrial thermal points and increasingly in module-type thermal points for residential consumers. The mathematical model is based on the mathematical equations describing this system and developed using the MATLAB - Simulink program. Thus, as a result of the simulations, we can see the evolutions in time of the water temperatures on the heating circuit and the domestic hot water circuit, as well as the quantity of heat delivered by them.

The Control and Model of Synchronous Generator on Ship

2012 ◽  
Vol 195-196 ◽  
pp. 1095-1101
Author(s):  
Le Luo ◽  
Lan Gao ◽  
Liang Chen ◽  
Liang Hu
Keyword(s):  
Mathematical Model ◽  
Control System ◽  
Simulation Model ◽  
Synchronous Generator ◽  
Excitation Control ◽  
Synchronous Generators ◽  
Simulation Test ◽  
Power Station ◽  
Model And Simulation ◽  
The Mathematical Model

This paper analyzes the characteristics of marine power station. The mathematical model and simulation model of synchronous generators AVR+PSS excitation control system was built. At last the simulation test of suddenly add load was did in MATLAB/simulink environment. The result shows that the excitation control system has well stability, rapidity and some robustness.

DEGREE OF REGENERATION OPTIMIZATION FOR CYCLES OF MICROGAS TURBINE PLANTS

2020 ◽  
Vol 3 ◽  
pp. 59-66
Author(s):  
A.V. DOLOGLONYAN ◽  
V.T. MATVIINKO
Keyword(s):  
Mathematical Model ◽  
Heat Exchanger ◽  
Surface Area ◽  
Hydraulic Resistance ◽  
Recovery Factor ◽  
Pressure Recovery ◽  
Area Optimization ◽  
Pressure Recovery Factor ◽  
The Mathematical Model ◽  
Regenerative Cycle

A consideration subject in article is the mathematical model of pressure recovery factor of microgas turbine plants (MGTP) regenerators which considers dependence of hydraulic resistance of the heat–exchanger on the its surface area. Optimization of a regenerative cycle of MGTP and a cycle with regeneration and the turbocompressor utilizer for the purpose of further increase in their profitability is performed. It is established that use of the offered model of pressure recovery factor on the air and gas side allows to find degree of regeneration heattechnical optimum. This model can be used at simplified and predesign of MGTP.

The Analysis of Plate Heat Exchanger in Central Heating Regulation of Indirect Connection Hot Water Heating System

2014 ◽  
Vol 584-586 ◽  
pp. 728-731
Author(s):  
Ming Hui Cui ◽  
Xin Wang ◽  
Ji Liang Liu
Keyword(s):  
Heat Exchanger ◽  
Heating System ◽  
Paper Analysis ◽  
Plate Heat Exchanger ◽  
Hot Water ◽  
Water Heating ◽  
Plate Heat ◽  
Indirect Connection ◽  
Central Heating ◽  
Regulation Method

Plate heat exchanger with unique advantages become dominant heat exchange equipment in heating engineering. But there is no heating regulation formula of plate exchanger applying in indirect connection hot water heating central heating regulation. This paper analysis the condition that the heating user’s system adopts quality regulation method and the hot water network system adopts quality-flow regulation method, obtain the regulation formulas of plate exchanger applying in indirect connection hot water heating central heating regulation, provides reliable theory basis on the operation regulation, energy –saving testing, etc. for indirect connection central heating system.

scholarly journals A multipurpose test rig for district heating substations: domestic hot water preparation and keep-warm function comparison

2019 ◽  
Vol 111 ◽  
pp. 06012
Author(s):  
Jad Al Koussa ◽  
Rutger Baeten ◽  
Nico Robeyn ◽  
Robbe Salenbien
Keyword(s):  
Heat Exchanger ◽  
Low Temperature ◽  
District Heating ◽  
Hot Water ◽  
Space Heating ◽  
Test Rig ◽  
Domestic Hot Water ◽  
Heat Demand

A well performing District Heating Substation (DHS) is crucial for the efficiency of the District Heating (DH), especially with the shift towards low temperature 4th generation DH systems. For this reason, testing and characterization of commercially available DHSs becomes important to estimate their effect on the DH network. Within the thermo-technical laboratory of EnergyVille, a multipurpose test rig has been built for testing DHSs. In this setup, different DH conditions and heat demand profiles for space heating and for Domestic Hot Water (DHW) can be emulated. Independent tests have been performed on 4 DHSs from three different manufacturers, focused on the DHW preparation for low DH supply temperature and on the stand-by/keep-warm operation of the substations. The latter maintains a certain temperature within the heat exchanger to avoid delays in the delivery of DHW. The results showed that improvements are needed on DHW production for lower DH supply temperatures. Also, enhancements are needed to reduce losses from the keep-warm function. Given that DH systems can have thousands of substations, this will reduce the overall losses and improve the performance of the DH network.

scholarly journals Techno-Economic Analysis of a Heat Pump Cycle Including a Three-Media Refrigerant/Phase Change Material/Water Heat Exchanger in the Hot Superheated Section for Efficient Domestic Hot Water Generation

2020 ◽  
Vol 10 (21) ◽  
pp. 7873
Author(s):  
Johann Emhofer ◽  
Klemens Marx ◽  
Tilman Barz ◽  
Felix Hochwallner ◽  
Luisa F. Cabeza ◽  
...  
Keyword(s):  
Energy Storage ◽  
Heat Exchanger ◽  
Economic Analysis ◽  
Phase Change ◽  
Heat Pump ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Hot Water ◽  
Domestic Hot Water ◽  
Change Material

Integration of a three-media refrigerant/phase change material (PCM)/water heat exchanger (RPW-HEX) in the hot superheated section of a heat pump (HP) system is a promising approach to save energy for domestic hot water (DHW) generation in multi-family houses. The RPW-HEX works as a desuperheater and as a latent thermal energy storage in the system. The latent thermal energy storage is charged during heating and cooling operation and discharged for DHW production. For this purpose, the water side of the RPW-HEX is connected to decentralized DHW storage devices. DHW consumption, building standards and climate, energy prices, material costs, and production costs are the constraints for the selection of the optimal storage size and RPW-HEX design. This contribution presents the techno-economic analysis of the RPW-HEX integrated into an R32 air source HP. With the aid of experimentally validated dynamic computer models, the optimal sizing of the RPW-HEX storage is discussed to maximize energy savings and to minimize the investment costs. The results are discussed in the context of a return of investment analysis, practical implementation aspects and energetic potential of the novel technology.

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.

Design and Simulation on Hydraulic Sleepless Speed Regulation System of Invariable Fertilizing Application

2014 ◽  
Vol 852 ◽  
pp. 665-670
Author(s):  
Jin Lin Wu ◽  
Li Xin Zhang ◽  
Jun Zhi Yu ◽  
Wei Bing Wang ◽  
Jia Hua Zhang
Keyword(s):  
Mathematical Model ◽  
Pid Control ◽  
Control Method ◽  
Transmission Error ◽  
System Stability ◽  
Regulation System ◽  
Speed Regulation ◽  
Model And Simulation ◽  
The Stability ◽  
The Mathematical Model

This paper proposes a hydraulic sleepless speed system for a invariable fertilizing application based on PLC, in order to enhance the stability of the hydraulic sleepless speed system and eventually achieve precise fertilizing. With particular emphasis on the stability of the hydraulic circuit and the actuation control method, mathematical model and simulation model for hydraulic sleepless speed system are established. More specifically, hydraulic sleepless speed system with stable oil circuit and oil pressure sensor is designed to ensure hydraulic system stability, while PID control algorithm is employed to compensate transmission error according to the mathematical model. The hydraulic sleepless speed system is then simulated in different PID control parameters. Simulations show that the results are reasonable and applicable, providing some theoretical guidance to the characteristics anticipation and test of hydraulic sleepless speed system. It is also found that when the PID parameter is chosen as =10, =0.08, =8, the fertilizing precision will be satisfied.

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