Optimization of Supply and Return Water Temperature of Single-Pipe Cross-Over Heating System for Energy Saving Reconstructed Building

2012 ◽  
pp. 1909-1913
Author(s):  
Xin Xie ◽  
Tian-Lin Zhang ◽  
Yan-Li Xu
Keyword(s):  
Water Temperature ◽  
Energy Saving ◽  
Heating System ◽  
Return Water ◽  
Single Pipe

Calculation and Analysis of Gravity Head Coefficient in Hot Water Heating System

2014 ◽  
Vol 580-583 ◽  
pp. 2432-2437
Author(s):  
Wen Wen Xie ◽  
Yong Zheng Fu
Keyword(s):  
Water Temperature ◽  
Mathematical Expectation ◽  
Heating System ◽  
Hot Water ◽  
Heating Period ◽  
Water Heating ◽  
Average Value ◽  
Return Water ◽  
Regulation Mode

This paper presented a method of mathematical expectation to calculate gravity head coefficient, and this method was applied to calculate the value of gravity head coefficient of some selected cities in China in different operation regulation mode and different design supply and return water temperature. The results show that gravity head coefficient calculated by this method reflects the average value during the whole heating period. It has more representative significance. When the temperature of design supply and return water in heating system is reduced, the gravity head coefficients change very little. In different operation regulation modes, the gravity head coefficients change larger. The gravity head coefficients have a certain difference in different areas.

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%.

Energy Saving Analysis on Solar Capillary Radiation Heating System

2013 ◽  
Vol 448-453 ◽  
pp. 2807-2814 ◽  
Author(s):  
Jin Shun Wu ◽  
Song Pan ◽  
Jun Wei ◽  
Hong Wei Liu ◽  
Yi Xuan Wei ◽  
...  
Keyword(s):  
Water Temperature ◽  
Energy Saving ◽  
Air Temperature ◽  
Indoor Air ◽  
Solar Collector ◽  
Experimental System ◽  
Heating System ◽  
Capillary Network ◽  
Water Volume ◽  
Low Grade

Radiation capillary used as air conditioning terminal lower the demand of heating water temperature. In additional, solar collectors could also supply amount of low grade energy for heating. Meanwhile, solar is a kind of renewable, sustainable and environment friendly energy. It will save a massive of conventional energy if make full use of solar for heating. In this paper, an experimental system made of solar collector, capillary network and pump was built up and tested. According to thermal load of experimental room, both solar collector area and capillary network area are calculated, and circulating water temperature was analyzed in detail. A summary is given about characteristics of heat storage and release of solar collector, indoor air temperature varying and amount of energy saving. The key factors affect efficiency of collector includes water volume, water temperature in tanker and indoor air temperature. The results show that the solar system can well meet the heating demand and the effect of energy saving is very significant compared to common heating system.

scholarly journals Energy Saving and Charging Discharging Characteristics of Multiple PCMs Subjected to Internal Air Flow

Fluids ◽  
2021 ◽  
Vol 6 (8) ◽  
pp. 275
Author(s):  
Ahmed J. Hamad
Keyword(s):  
Phase Change ◽  
Energy Saving ◽  
Air Temperature ◽  
Temperature Control ◽  
Phase Change Materials ◽  
Energy Savings ◽  
Heating System ◽  
Air Heating ◽  
Room Model ◽  
Model Temperature

One essential utilization of phase change materials as energy storage materials is energy saving and temperature control in air conditioning and indirect solar air drying systems. This study presents an experimental investigation evaluating the characteristics and energy savings of multiple phase change materials subjected to internal flow in an air heating system during charging and discharging cycles. The experimental tests were conducted using a test rig consisting of two main parts, an air supply duct and a room model equipped with phase change materials (PCMs) placed in rectangular aluminum panels. Analysis of the results was based on three test cases: PCM1 (Paraffin wax) placed in the air duct was used alone in the first case; PCM2 (RT–42) placed in the room model was used alone in the second case; and in the third case, the two PCMs (PCM1 and PCM2) were used at the same time. The results revealed a significant improvement in the energy savings and room model temperature control for the air heating system incorporated with multiple PCMs compared with that of a single PCM. Complete melting during the charging cycle occurred at temperatures in the range of 57–60 °C for PCM1 and 38–43 °C for PCM2, respectively, thereby validating the reported PCMs’ melting–solidification results. Multiple PCMs maintained the room air temperature at the desired range of 35–45.2 °C in the air heating applications by minimizing the air temperature fluctuations. The augmentation in discharging time and improvement in the room model temperature using multiple PCMs were about 28.4% higher than those without the use of PCMs. The total energy saving using two PCMs was higher by about 29.5% and 46.7% compared with the use of PCM1 and PCM2, respectively. It can be concluded that multiple PCMs have revealed higher energy savings and thermal stability for the air heating system considered in the current study.

scholarly journals METHODOLOGY OF THE PRIMARY DATA RECONSTRUCTION OF SINGLE PIPE HEATING SYSTEMS/VIENVAMZDŽIŲ ŠILDYMO SISTEMŲ PIRMINIŲ DUOMENŲ NUSTATYMO METODIKA

1999 ◽  
Vol 5 (5) ◽  
pp. 318-322
Author(s):  
Edvardas Tuomas ◽  
Saulius Neverbickas
Keyword(s):  
World War Ii ◽  
District Heating ◽  
Heating System ◽  
Heat Fluxes ◽  
Primary Data ◽  
Complex Coefficient ◽  
Heating Systems ◽  
Pipe System ◽  
Central Heating ◽  
Single Pipe

The majority of dwellings in Lithuania are situated in blocks of flats. The dwellings were built after World War II and they are heated by single pipe central heating systems, connected to district heating. The dwellers are not quite satisfied with such a heating system and try to improve it, but do that in a wrong way, by increasing the surface of radiators. Such means lead to violation of thermal regime and comfort conditions for other dwellers. There exists sometimes the necessity of reconstructing premises and together—the heating system. During the reconstruction the primary heat fluxes from radiators should be known, but very often such data are lost and only the size of radiators (number of sections) are known. To reconstruct the required primary data for single pipe systems is complicated because the temperatures of inlet and outlet water for radiators are unknown. In this article the methodology is proposed how to perform the calculations leading to the required data. The aim of calculations is the establishment of heat fluxes from each radiator connected to the riser. Heat flux from radiator can be calculated according the formula (1) but the complex coefficient is unknown. It could be found from formulae (2) but some magnitudes are unknown. According to the proposed methodology the values of unknown magnitudes are taken approximately and calculations are performed with iterations. In such a way the flow rate of water in riser is established from formula (3), which is the same for each radiator (the property of single pipe system). From formulas (3) and (4) an equation is produced (5), and is used for calculations of unknown temperatures. The equation (6) is used for calculation of heat fluxes from radiators. To carry out the above-mentioned calculations without computer practically is impossible due to many cycles of iteration. The programme was prepared to make easy all these calculations. The scheme of algorithm of programme is given in Fig 1. An example of calculation is given in this article. Calculations were fulfilled by newly created programme. The riser chosen for calculation is shown in Fig 2. The results of calculation are given in Table 1. The table shows that according to the proposed methodology the programme based on it can be used for reconstruction of primary data of single pipe heating systems successfully.

scholarly journals Field Study Of A Radiant Heating System For Sleep Thermal Comfort And Potential Energy Saving

2021 ◽  
Author(s):  
Christopher L. K. Wang
Keyword(s):  
Potential Energy ◽  
Thermal Comfort ◽  
Energy Saving ◽  
Energy Savings ◽  
Thermal Environment ◽  
Residential Buildings ◽  
Thermal Conditions ◽  
Heating System ◽  
The Body ◽  
Radiant Temperature

As sleep is unconscious, the traditional definition of thermal comfort with conscious judgment does not apply. In this thesis sleep thermal comfort is defined as the thermal condition which enables sleep to most efficiently rejuvenate the body and mind. A comfort model was developed to stimulate the respective thermal environment required to achieve the desired body thermal conditions and a new infrared sphere method was developed to measure mean radiant temperature. Existing heating conditions according to building code conditions during sleeping hours was calculated to likely overheat a sleeping person and allowed energy saving potential by reducing nighttime heating set points. Experimenting with existing radiantly and forced air heated residential buildings, it was confirmed that thermal environment was too hot for comfortable sleep and that the infrared sphere method shows promise. With the site data, potential energy savings were calculated and around 10% of energy consumption reduction may be achieved during peak heating.

scholarly journals Efficient central heating and modern heat sources

2013 ◽  
Vol 7 (4) ◽  
pp. 28-33
Author(s):  
Monika Pawlita
Keyword(s):  
Energy Saving ◽  
Calorific Value ◽  
Cost Effective ◽  
Weather Conditions ◽  
Heating System ◽  
Heat Pumps ◽  
Single Family ◽  
Heating Source ◽  
The Cost ◽  
Family House

Background: The methods of heating houses with system components determine the energy-saving systems. Energy-saving solutions allow to maintain comfortable conditions in the house, while minimizing the cost associated with its operation and at the same time helping to protect natural environment. The examples of such solutions include condensing boilers, heat pumps and solar collectors.Material and methods: The object of the analysis in this paper is typical single-family house occupying the area of 150 m². The comparison of analyzed heating system for a single-family house, including modern energy sources, allows the assessment of the most cost-effective method of heating. Results: Choosing rational method of heating for a single-family house is dictated mainly by economic reasons. The efficiency of the heating sources is also very important. In addition, an important factor is a heating period, which depends on the weather conditions in a given year.Conclusions: The costs of fuel/energy are still growing. Fuel selection is determined mainly by fuel calorific value and the price. To select the type of the heating source one must take into account the cost of kWh of heat.

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