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Heat measuring method for solar water heating system

A technology of solar water heating and metering method, applied in the field of solar thermal utilization, can solve the problems of unusable, expensive calorimeter and flowmeter, large measurement error, etc., and achieve the effect of reducing cost and easy calibration

Inactive Publication Date: 2012-10-17
北京创意博能源科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Calorimeters and flowmeters are relatively expensive, especially for solar water heating systems with large areas. Due to the thick main pipes, calorimeters or flowmeters with large diameters must be used, and the price has doubled.
The heat meter or flow meter is not needed in the operation control of the solar water heating system. After installation, it is only a measuring tool, not a necessary equipment for operation, so ordinary users are not willing to spend more money to install it for metering
[0015] Since the main purpose of the solar system is to produce hot water, the temperature of the water entering the collector may also be very high in the thermal cycle mode, which requires the installation of high-temperature calorimeters or flow meters, which will cost more
[0016] In addition, due to scale problems, heat meters or flow meters (such as turbine flow meters, vortex flow meters, and hot water meters, etc.) connected to pipelines will be blocked by scale after a period of use, making them unusable and must be replaced.
If an ultrasonic calorimeter or flowmeter is used, after the scale is attached to the pipe wall, the measurement error will be extremely large, and even the measurement will not be possible due to signal attenuation.
Moreover, almost all flowmeters will have larger and larger errors as they are used at any time, and they need to be calibrated regularly
The calibration of the flowmeter generally needs to be disassembled, which will be very troublesome for the system in use

Method used

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  • Heat measuring method for solar water heating system
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  • Heat measuring method for solar water heating system

Examples

Experimental program
Comparison scheme
Effect test

specific Embodiment approach 1

[0087] A solar hot water system with collectors of 12.5m 2 , the volume of the water tank is 1m 3 , the height of the water tank is 1.2m, and the temperature difference cycle operation mode is adopted. The sun was better in the morning. At that time, the water level of the water tank was 85%, that is, the water level was 1.02 meters high, and the water temperature was 21.0°C. At 11:35:40, the water pump starts to circulate, and at 11:41:48, the water pump stops running for a total of 368 seconds. At this time, the water temperature of the water tank rises to 22.5°C. Because the user does not use hot water at this time, nor does it flow into the water tank. Internal water replenishment (controller output control is required when using water or water replenishment), so the flow calculation conditions are met. At this time, the average value of the collector outlet temperature T1 is 26.8°C, and the average value of the inlet temperature T2 is 21.7°C. According to formula (5) , ...

specific Embodiment approach 2

[0093] A solar water heating system adopts the constant temperature outlet water operation mode, and the collector is 25m 2 , the volume of the water tank is 2m 3 , the height inside the tank is 2.4m. At that time, the water level of the water tank was 25%, that is, the water level was 0.6 meters high, and the water temperature was 35.2°C. The solenoid valve starts at 9:16:56, and the water pump stops running at 9:17:56 for a total of 60 seconds. At this time, the water temperature of the water tank rises to 36.5°C. Since the user does not use hot water at this time, the flow calculation is satisfied. Conditions, at this time the average value of the collector outlet temperature T1 is 47.5°C, and the average value of the inlet temperature T2 is 18.4°C, according to the formula (6), the flow rate can be calculated:

[0094] m · = 2000 × 0.672 × ( ...

specific Embodiment approach 3

[0097] A solar hot water system with a collector area of ​​1885m 2 , the volume of the water tank is 50m 3 , when the water tank is not full, it adopts the constant temperature water outlet operation mode. When the water tank is full, it changes to the temperature difference circulation mode. When the water volume is less than 50%, it is changed to the constant temperature water outlet operation mode. The collector array is divided into four sections, and each section has a circulating water pump and a water supply solenoid valve. The controller is a PLC controller, which respectively measures the top and bottom temperatures of the collectors in the four parts, and controls the water pumps and water supply solenoid valves in the four parts respectively.

[0098] Because the flow rate may be different in different operating modes, so according to the operating mode, if it is a temperature difference circulation mode, if the flow calculation conditions are met, calculate the co...

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Abstract

The invention discloses a heat measuring method for a solar water heating system. The heat measuring method comprises the following steps of: firstly, recording changes of the following parameters during the starting of a circulating water pump or a water feeding electromagnetic valve of a solar heat collector when judging that the circulating water pump or the water feeding electromagnetic valve of the solar heat collector is started but a water feeding electromagnetic valve and a water consuming electromagnetic valve of a water tank are not started: the temperature of an inlet of the solar heat collector, the temperature of an outlet of the solar heat collector, and the water level and the water temperature in the water tank; secondly, calculating the heat gain of the water in the water tank through the changes of the water temperature and the water level in the water tank during the starting; thirdly, obtaining the average flow of the water by dividing the heat gain of the water in the water tank by the average temperature difference of the inlet and the outlet of the solar heat collector from the time before starting to the time after stopping, the specific heat capacity and the starting time; and finally, calculating the heat gain of the solar heat collector to realize heat measuring by using the average flow and the inlet temperature and the outlet temperature of the solar heat collector each time when the circulating water pump or the water feeding electromagnetic valve of the solar heat collector is started.

Description

technical field [0001] The invention relates to a solar heat utilization technology, in particular to a heat energy metering method for a solar water heating system. Background technique [0002] Solar water heating systems generally consist of solar collectors or collector arrays (hereinafter referred to as collectors), water tanks, pumps, solenoid valves, pipelines and controllers. [0003] Such as figure 1 As shown, it is a relatively typical system. The heat collector 1 absorbs sunlight and converts it into heat energy, and heats the water in the heat collector. When the water temperature T1 at the top of the heat collector 1 rises to the temperature difference with the water temperature T3 in the water tank After the set temperature difference is reached (such as 7°C), the water pump 3 starts to pump the cold water in the water tank into the heat collector 1, push out the hot water in the heat collector 1, and return it to the water tank 2, as the heat collector After...

Claims

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Application Information

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IPC IPC(8): G01K17/08
Inventor 邹怀松唐轩张一宇曲向林霍岩梁引俊
Owner 北京创意博能源科技有限公司