Performance Estimate for Design of Storage-Type Domestic Electrical Water-Heaters Based on the CFD Simulation

2010 ◽  
Vol 26-28 ◽  
pp. 732-735
Author(s):  
Zhi Jun Zhang ◽  
Shi Wei Zhang ◽  
Cheng Hai Xu
Keyword(s):  
Water Temperature ◽  
Cfd Simulation ◽  
Cold Water ◽  
Discharge Rate ◽  
Water Discharge ◽  
Hot Water ◽  
New Method ◽  
Dynamics Simulation ◽  
Water Heater ◽  
Discharge Efficiency

The 3D physical model of the electrical water heater was built. The water-heater performance of two kind structures was resolved by computer fluid dynamics simulation (CFD). The heater performance is characterized by a new method rather than that the discharge efficiency, extraction efficiency and fraction of heat recoverable. The new method is based on the constant discharge water temperature and rate for end user, 5L/min and 43°C that include the hot water from EWH and cold water from outside EWH. But the water discharge rate from EWH was variable as the water temperature discharge from EWH was variable. The discharge efficiency of conventional EWH was 79.312%, and the discharge efficiency of improved EWH was 84.97%. Compared with the traditional method, it is more close to the user using reality condition.

A New Performance Estimate Method for Design of Storage-Type Domestic Electrical Water-Heaters Based on the CFD Simulation

2010 ◽  
Vol 129-131 ◽  
pp. 463-466
Author(s):  
Li Li Zhao ◽  
Zhi Jun Zhang ◽  
Shi Wei Zhang
Keyword(s):  
Water Temperature ◽  
Cfd Simulation ◽  
Cold Water ◽  
Discharge Rate ◽  
Water Discharge ◽  
Hot Water ◽  
New Method ◽  
Dynamics Simulation ◽  
Water Heater ◽  
Water Heaters

The 3D physical model of the electrical water heater was built. The water-heater performance was resolved by computer fluid dynamics simulation (CFD). The heater performance is characterized by a new method rather than that the discharge efficiency, extraction efficiency and fraction of heat recoverable. The new method is based on the constant discharge water temperature and rate for end user, 5L/min and 43°C that include the hot water from EWH and cold water from outside EWH. But the water discharge rate from EWH was variable as the water temperature discharge from EWH was variable. Compared with the traditional method, it is more close to the user using reality condition.

Performance Study of Structure Improvement Design for Storage-Type Domestic Electrical Water-Heaters Based on the CFD Simulation

2010 ◽  
Vol 129-131 ◽  
pp. 602-606
Author(s):  
Zhi Jun Zhang ◽  
Shi Wei Zhang ◽  
Cheng Hai Xu
Keyword(s):  
Cfd Simulation ◽  
Discharge Rate ◽  
Hot Water ◽  
Dynamics Simulation ◽  
Water Tank ◽  
Performance Study ◽  
Water Heater ◽  
Water Heaters ◽  
Traditional Structure ◽  
Structure Improvement

The 3D physical model with two different structure of the electrical water heater was built. The performance of water heater was studied by computer fluid dynamics simulation (CFD). The heater performance is characterized the discharge efficiency, extraction efficiency and fraction of heat recoverable. It was 73.7%, 45% and 49.8% respectively with conventional structure, and it was 81.1%, 54.1% and 59.6% respectively of improved structure with discharge rate was 5L/min when all initial hot water temperature was 90°C. The temperature distribution of different discharged stage was also disclosure. The water inner the water tank of improved structure has the better thermal stratification than traditional structure. It was also agreed with the water heat performance.

Performance Study for Storage-Type Domestic Electrical Water-Heaters with Double Tank Based on the CFD Simulation

2010 ◽  
Vol 29-32 ◽  
pp. 1701-1705
Author(s):  
De Xi Wang ◽  
Zhi Jun Zhang
Keyword(s):  
Cfd Simulation ◽  
Discharge Rate ◽  
Hot Water ◽  
Dynamics Simulation ◽  
Water Tank ◽  
Performance Study ◽  
Water Heater ◽  
Water Heaters ◽  
Computer Fluid Dynamics ◽  
The Mathematical Model

The 3D physical model of the electrical water heater was built. The mathematical model of hot flow was resolved by computer fluid dynamics simulation (CFD). The effects of the rate of water draw on the heater performance have been investigated. The heater performance is characterized the discharge efficiency, extraction efficiency and fraction of heat recoverable. It was 85.9%, 66.0% and 70.9% respectively, and it was 74.0%, 27.3% and 39.9% respectively with discharge rate was 10L/min when all initial hot water temperature was 70°C. The water inner the water tank of draw rate 5L/min was well thermal stratification. It was also expatiated by the distribution temperature of CFD simulation.

Performance Study of Storage-Type Domestic Electrical Water-Heaters with Wedged Inlet: Unsteady Water Discharge Rate

2010 ◽  
Vol 44-47 ◽  
pp. 299-303
Author(s):  
Zhi Jun Zhang ◽  
Shi Wei Zhang ◽  
Cheng Hai Xu
Keyword(s):  
Temperature Profile ◽  
Discharge Rate ◽  
Water Discharge ◽  
Dynamics Simulation ◽  
Performance Study ◽  
Water Heaters ◽  
Computer Fluid Dynamics ◽  
Unsteady Discharge ◽  
Discharge Efficiency ◽  
Storage Type

The unsteady water discharge rate on performance of storage-type domestic electrical water-heaters with wedged inlet was studied by computer fluid dynamics simulation (CFD). The results were compared with those of conventional design EWHs having the same tank size. The heater performance is characterized the discharge efficiency, extraction efficiency and fraction of heat recoverable. The water draw-off temperature profile of steady and unsteady water discharge rate has nothing difference for wedged inlet structure, both curve was overlapped. The almost the same energy utility efficiency was gotten both steady and unsteady discharge rate for wedged inlet structure. The obviously difference of water draw-off temperature profile was shown for conventional inlet structure. Water draw-off temperature profile of unsteady discharge rate was decreased faster than steady discharge rate. The energy utility efficiency of unsteady discharge rate was also lower than steady discharge rate. The results were shown that the wedged inlet structure heater has excellent performance for energy utility efficiency under unsteady discharge rate.

scholarly journals A Compact and Fast Temperature-Response Heat Pump Water Heater

1997 ◽  
Author(s):  
B. J. Huang ◽  
F. H. Lin
Keyword(s):  
Heat Pump ◽  
Water Discharge ◽  
Temperature Response ◽  
Control Device ◽  
Hot Water ◽  
Water Heater ◽  
Supply Tank ◽  
Heat Pump Water Heater ◽  
Temperature Recovery ◽  
Line Switching

A compact and fast temperature-response heat pump water heater was designed using multiple tanks and a sequential control device. The supply tank was heated as a priority by a freon-line switching device to increase the temperature recovery speed. A dual-tank prototype with 100-liter capacity was built and tested. The experimental results show that the time for temperature recovery of the supply tank from 42°C to 54°C reaches 10–20 minutes and COP reaches 2.0–3.0 during various seasons. The prototype tests show that an energy saving around 50%–70% as compared to the electrical water heater can be obtained. The hot water discharge efficiency of the heat pump is 0.912.

scholarly journals Non-residential water demand model validated with extensive measurements and surveys

2013 ◽  
Vol 6 (2) ◽  
pp. 99-114 ◽  
Author(s):  
E. J. Pieterse-Quirijns ◽  
E. J. M. Blokker ◽  
E. van der Blom ◽  
J. H. G. Vreeburg
Keyword(s):  
Water Demand ◽  
Cold Water ◽  
Residential Buildings ◽  
Water System ◽  
Hot Water ◽  
Demand Model ◽  
Water Heater ◽  
Peak Demand ◽  
Demand Equations ◽  
Proper Estimation

Abstract. Existing Dutch guidelines for the design of the drinking water and hot water system of non-residential buildings are based on outdated assumptions on peak water demand or on unfounded assumptions on hot water demand. They generally overestimate peak demand values required for the design of an efficient and reliable water system. Recently, a procedure was developed based on the end-use model SIMDEUM to derive design-demand-equations for peak demand values of both cold and hot water during various time steps for several types and sizes of non-residential buildings, viz. offices, hotels and nursing homes. In this paper, the design-demand-equations are validated with measurements of cold and hot water patterns on a per second base and with surveys. The good correlation between the simulated water demand patterns and the measured patterns indicates that the basis of the design-demand-equations, the SIMDEUM simulated standardised buildings, is solid. Surveys were held to investigate whether the construction of the standardised buildings based on the dominant variable corresponds with practice. Surveys show that it is difficult to find relationships to equip the standardised buildings with users and appliances. However, the validation proves that with a proper estimation of the number of users and appliances in only the dominant functional room of the standardised buildings, SIMDEUM renders a realistic cold and hot water diurnal demand pattern. Furthermore, the new design-demand-equations based on these standardised buildings give a better prediction of the measured peak values for cold water flow than the existing guidelines. Moreover, the new design-demand-equations can predict hot water use well. In this paper it is illustrated that the new design-demand-equations lead to reliable and improved designs of building installations and water heater capacity, resulting in more hygienic and economical installations.

The Device of the Automatic Backflow in Solar Water Heater-Temperature Control and Backflow for Pipe of Water Heater

2013 ◽  
Vol 827 ◽  
pp. 99-104
Author(s):  
Bin Li ◽  
Xi Chen ◽  
Xin Hao Li ◽  
Lu Kuan Ma ◽  
Wen Bo Lu ◽  
...  
Keyword(s):  
Water Resources ◽  
Cold Water ◽  
Hot Water ◽  
Water Tank ◽  
Solar Water Heater ◽  
Recycle Water ◽  
Delay Effect ◽  
Water Heater ◽  
Domestic Water ◽  
Solar Water

Now in general use in solar water heater, there is a long pipeline between water heater and tap, we have to empty the stored cold water before we use the hot water; and usually the water cannot meet required temperature due to the heating delay effect, thus the water also should be emptied, which leads to a waste of water resources. In order to solve this water wastage, we propose a device which can help to control the temperature and backflow of the water in water heater. The device accomplishes backflow of cold water automatically under the effect of gravity, and refluxed water will be stored in the recycle-water tank, thus ensuring the result that the water temperature satisfies the requirement. After the recycle-water tank is full, it will trigger the buoy to control the relay switch, then the water pump start to work to force the water into the water heater tank. Thus, realizing the recycling of water. This device can significantly save water resources in domestic water, and it has a broad market prospect.

scholarly journals Application research of intelligent monitoring system of longsheng hot spring water temperature based on Internet of Things

2019 ◽  
Vol 23 (5 Part A) ◽  
pp. 2613-2622
Author(s):  
Bi Li ◽  
Shi Zheng
Keyword(s):  
Water Temperature ◽  
Monitoring System ◽  
Hot Springs ◽  
Cold Water ◽  
Hot Spring ◽  
Spring Water ◽  
Temperature Monitoring ◽  
Hot Water ◽  
Single Chip ◽  
Main Station

Guangxi Guilin area, China, is rich in hot spring resources. In this paper, a hot spring water temperature monitoring system is developed for longsheng hot springs. Mainly using the hot water of eye of hot springs as the heat source, designing a set of multi-point temperature monitoring system with single-chip and multi-slave as the core of the single-chip microcomputer and wireless and bi-directional transmission for the main station and multiple slave stations to realize automatic temperature monitoring. The system slave station can exchange geothermal water with high temperature extracted from the eye of hot springs and cold water, and automatically control the temperature of the hot spring pool to reach a set value range by controlling the flow rate of the cold water. At the same time, the main station can complete the tasks of monitoring system by setting control commands such as temperature.

scholarly journals Experimental determination of cold water temperature at the inlet to solar water storage tanks

2019 ◽  
Vol 116 ◽  
pp. 00106 ◽  
Author(s):  
Miroslaw Zukowski
Keyword(s):  
Water Temperature ◽  
Cold Water ◽  
Tap Water ◽  
Water System ◽  
District Heating ◽  
Hot Water ◽  
Storage Tanks ◽  
Climate Conditions ◽  
Cold Water Temperature

In the present work, results of experimental research on the mains water temperature supplying the Solar Domestic Hot Water system in the period from 2016 to 2018 are shown. The test object is located in the Hotel for Research Assistants on Bialystok University of Technology campus in Poland. One of the elements that will guarantee the correct energy balance of a hot tap-water system is the exact determination of the cold water temperature. The aim of this study is estimation of the temperature of the mains water flowing into the district heating substation and the water feeding directly the heat storage tanks. The research results showed that the average value of the cold water was 14.09°C during the 3 years of measurements. Moreover, it was shown that this temperature increased by about 0.4°C as a result of heat exchange with the air inside the substation. In the article, the author proposed modifications of coefficients in a commonly used model developed by National Renewable Energy Laboratory for determining the temperature of mains water in energy simulations. The proposed changes allow for accurate modelling of the cold water temperature under the climate conditions of north-eastern Poland.

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