A Novel “Wireless On-Off Control” Technique for Household Heat Adjusting and Metering in District Heating System

2009 ◽  
Author(s):  
Lanbin Liu ◽  
Lin Fu ◽  
Yi Jiang
Keyword(s):  
Energy Consumption ◽  
District Heating ◽  
Heating System ◽  
Control Technique ◽  
Space Heating ◽  
Indoor Temperature ◽  
District Heating System ◽  
The Real ◽  
Temperature Controller ◽  
The Difference

A large-scale survey and on-site measurements on space heating systems in Beijing has been carried out since 2005. Detailed analysis shows that the improvement of system regulation to adjust the heating demand and to avoid over-heating in building space is the key to reduce the heating energy consumption. It also indicates that combined heat and power (CHP) based district heating network is the most suitable solution for the space heating in Chinese northern cities. Thus, the priority should be in the research and development of new techniques to improve heating system regulation and control. In China, there are three reasons for poor heating system regulation: • the lack of control devices in space heating system, • the complex and inconvenient operation, and • the insufficient motivation because the charging policy is based on the heating areas. Field test results show that 20% to 30% of thermal energy is wasted because of the poor heating system regulation. In order to solve these problems, a novel “wireless on-off control” system for household heat adjusting and metering has been proposed. This technology works in the following way: 1) a calorimeter is installed at each building to measure the total heat consumption of the whole building; 2) an on-off valve is installed for each household and an indoor temperature controller is provided for the occupants. The operation procedure is as follows. First, the desired indoor temperature is set by the users through the indoor temperature controller and wireless signals are sent to the on-off valve. Then the on-off valve detects the real indoor temperature and determines the difference between the real temperature and the set value. After this, the valve calculates the proportion of on-time to off-time in the next step according to the thermal strategies programmed in the valve’ CPU. Then the valve is controlled according to the proportion to maintain the desired indoor temperature; and 3) the heating cost of each household can be allocated according to its heating area and the accumulative open time of the valve. The proposed technique has been applied in fifteen residential communities with the total areas of 1,200,000 m2. The testing results show that: 1) indoor temperatures were accurately controlled within +/− 0.5 °C around the set point, so that the problem of overheating can be avoided; 2) the difference of temperature in different room is less than 1 °C. Therefore, if radiators in each room are designed reasonably, to control the temperature of one room can meet the requirements of the entire user’s apartment; 3) energy consumption in the controlled household was approximately 30% lower than the uncontrolled household with the same building type.

An Improved Method to Evaluate Energy Efficiency of Large-Scale District Heating System with Boiler Heat Source

2013 ◽  
Vol 448-453 ◽  
pp. 2856-2859
Author(s):  
Wei Na ◽  
Yan Song ◽  
Lei Yang
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Large Scale ◽  
District Heating ◽  
Heating System ◽  
Improved Method ◽  
District Heating System ◽  
Energy Efficiency Improvement ◽  
The Difference ◽  
Heating Energy Consumption

Over 600 million square meter heating area use the district heating system in Beijing up to 2013. The construction and operation level of many heating systems are diverse. It leads to the difference in the heating energy consumption and cost. The obstacles that impacts on the energy efficiency improvement for the district heating system in Beijing were presented. The primary job to reduce the gross heating energy consumption is to evaluate the energy efficiency of the heating system, reasonably. The aim of the paper was to provide an improved method to evaluate the energy efficiency of a district heat system.The energy conversion between the different typical parts of a heating system was discussed: the source, the primary network, the secondary network, the heat exchanger station and the building. Also, six district heating system in Beijing was evaluated by the method to illustrate the proposed technique.

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.

scholarly journals District heating system simulation considering consumer and pump operation features

Vestnik MGSU ◽  
2019 ◽  
pp. 748-755 ◽  
Author(s):  
Saule K. Abildinova ◽  
Stanislav V. Chicherin
Keyword(s):  
Mathematical Model ◽  
Energy Consumption ◽  
District Heating ◽  
Heating System ◽  
Hot Water ◽  
Water Supply Systems ◽  
Problem Solution ◽  
District Heating System ◽  
Pump Station ◽  
Pump Equipment

Introduction. The purpose of this investigation is to show what changes introduced in the mathematical model of a district heating system are capable of considerable improving the convergence of simulation results and actual data. The study evaluates the work of heating supply establishments with their customers as well as analysis of the ways of enhancing pump equipment efficiency that allows saving electric energy or increasing output at the same energy consumption. Materials and methods. Engineering acceptance of newly introduced and reconstructed facilities is conducted, heat loads are corrected, disconnections and recurrent connections of indebted consumers are carried out. Studying data submitted by a local heat supply establishment shows that pump seals made from iron and steel are subject accelerated wear in the course of operation. Results. Three variants of the problem solution are suggested: making seals from bronze or stainless steel, prevention of unjustified increase of seal clearances as well as using labyrinth pump seals. This will allow increasing pump equipment efficiency by 5 to 7 % and save about 2 × 105 kW∙h of electrical energy for every pump or increase of output at the same energy consumption. Taking into account that a pump station is a part of the district heating system and unmachined inner surfaces of the pumps have a significant roughness, grinding of these surfaces can improve their hydraulic characteristics of the pumps. In the scope of the suggested method, the entire district heating system is considered not in the situation when actual load is equal to the sum of all the design loads and the pump equipment has manufacturer’s parameters, but accounting actual loads and characteristics. Conclusions. Mathematical model of district heating system heating and hydraulic mode that takes issues mentioned above into consideration would allow simulating joint operation of the heating and hot water supply systems at transient operation modes with higher accuracy.

scholarly journals Development and Test of a Novel Electronic Radiator Thermostat with a Return Temperature Limiting Function

Energies ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 367
Author(s):  
Michele Tunzi ◽  
Dorte Skaarup Østergaard ◽  
Svend Svendsen
Keyword(s):  
Temperature Sensor ◽  
State Of The Art ◽  
District Heating ◽  
Control Valve ◽  
Heating System ◽  
Fourth Generation ◽  
Space Heating ◽  
Heating Systems ◽  
Valve Opening ◽  
The Difference

Automated hydronic balancing in space heating systems is crucial for the fourth-generation district heating transition. The current manual balancing requires labor- and time-consuming activities. This article presents the field results of an innovative electronic radiator thermostat tested on two Danish multi-family buildings. The prototypes had an additional return temperature sensor on each radiator and an algorithm was used to accurately control valve opening to ensure automated hydronic balancing. The results highlighted that the new thermostat performed as expected and helped secure the cooling of district heating temperatures —defined as the difference between supply and return temperature—4–12 °C higher during the test compared to results obtained in 2020, when the prototypes were replaced with state-of-the-art thermostats in the first building. The measurements from the other building illustrated how only two uncontrolled radiators out of 175 could contaminate the overall return temperature. The remote connection of the thermostats helped pinpoint the faults in the heating system, although the end-users were not experiencing any discomfort, and secure, after fixing the problems, a return temperature of 35 °C. Future designs may consider integrating a safety functionality to close the valve or limit the flow in case of damage or malfunction to avoid a few radiators compromising the low-temperature operation of an entire building before the cause of the problem has been identified.

scholarly journals Impact of Domestic Hot Water Systems on District Heating Temperatures

Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4694
Author(s):  
Tina Lidberg ◽  
Thomas Olofsson ◽  
Louise Ödlund
Keyword(s):  
Low Temperature ◽  
District Heating ◽  
Heating System ◽  
Hot Water ◽  
Space Heating ◽  
Circulation System ◽  
District Heating System ◽  
Domestic Hot Water ◽  
Temperature Levels ◽  
The Impact

When buildings become more energy effective, the temperature levels of district heating systems need to be lower to decrease the losses from the distribution system and to keep district heating a competitive alternative on the heating market. For this reason, buildings that are refurbished need to be adapted to suit low-temperature district heating. The aim of this paper is to examine whether four different energy refurbishment packages (ERPs) can be used for lowering the temperature need of a multi-family buildings space heating and domestic hot water (DHW) system as well as to analyse the impact of the DHW circulation system on the return temperature. The results show that for all ERPs examined in this study, the space heating supply temperature agreed well with the temperature levels of a low-temperature district heating system. The results show that the temperature need of the DHW system will determine the supply temperature of the district heating system. In addition, the amount of days with heating demand decreases for all ERPs, which further increases the influence of the DHW system on the district heating system. In conclusion, the DHW system needs to be improved to enable the temperature levels of a low-temperature district heating system.

Physical-Rule Based Adaptive Neuro-Fuzzy Inferential Sensor vs. GA-BP Based Prediction Model in Indoor Temperature Predicting

2012 ◽  
Vol 594-597 ◽  
pp. 2179-2185
Author(s):  
Liang Huang ◽  
Zai Yi Liao
Keyword(s):  
Prediction Models ◽  
Back Propagation ◽  
District Heating ◽  
Heating System ◽  
Good Prediction ◽  
Indoor Temperature ◽  
District Heating System ◽  
Rule Based ◽  
Neuro Fuzzy ◽  
Indoor Comfort

The previous research on temperature prediction presented different approaches which are physical-rule based adaptive neuro-fuzzy inferential sensor (ANFIS) model and GA-BP (genetic algorithm back propagation) based model to estimate the average indoor temperature in the building environment. Their good prediction performances improved energy efficiency of district heating system and indoor comfort ratio. However, either of these two models has its drawback in a certain condition. In this paper, the two prediction models are reviewed and evaluated by three performance measures (RMSE, RMS, and R2). Their limitations are discussed and potential solution is proposed.

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