Technical disclosure! Process standard for installation of solar water heating equipment and pipeline

This process standard is applicable to the installation of ordinary flat plate straight pipe solar water heater and pipeline in civil and general industrial buildings.

1、 Material requirements

（1） The type of solar water heater shall meet the design requirements. The finished product should have production certificate.

（2） Material requirements of collector:

The transparent cover is required to have high transmittance of short wave solar radiation, high reflection and absorption of long wave thermal radiation, good weather resistance, durability, heat resistance, light weight and certain strength. It is better to use 3-5mm thick tempered glass with less iron content.

2. The surface of heat collecting plate and heat collecting tube shall be black paint with weather resistance, high adhesion and high strength.

3. Copper and stainless steel tubes should be used for the materials with high thermal conductivity, smooth inner wall, low flow friction, not easy to rust, not polluting water quality, high strength, good durability and easy processing; Generally, galvanized carbon steel pipe or alloy aluminum pipe is used. The tubular collector can be made of 2-3mm thick plastic pipe (PVC).

4. The heat collecting plate should have good thermal conductivity and durability, and not easy to rust. Aluminum alloy plate, aluminum plate, stainless steel plate or steel plate with anti-corrosion treatment should be used.

The 5 collector should have thermal insulation layer and shell. The insulation layer can be made of mineral wool, glass wool and foam plastics. The shell can be made of wood, steel plate and FRP.

（3） The pipes and fittings of hot water system should be galvanized carbon steel pipes and fittings. See Chapter 2 for requirements.

2、 Main machines and tools

1 machinery: vertical crane, threading machine, grinding wheel saw, electric hammer, electric drill, secondary electric welding machine, electric pressure test pump, etc.

Tools: threading plate, pipe wrench, spanner, hacksaw, pressure clamp, hammer, bending machine, electric welding tools, etc.

Other tools: steel tape, box ruler, square, level ruler, line drop, protractor, etc.

3、 Operating conditions

1. The solar water heater installed on the roof should be installed after the protective layer is finished.

2. The roof structure shall be able to bear the load of new solar water heater equipment.

3. The solar water heater located on the balcony should be installed on the balcony fence and provided with safety protection measures.

4. The solar water heater should be installed with enough sunshine intensity.

4、 Operation technology

（2） Installation Preparation:

According to the design requirements, open the box and check whether the specifications and models of the water heater are correct and whether the accessories are complete.

2. Clean up the scene, draw lines and position.

（3） The fabrication and installation of support frame shall be made according to the design details, and generally the finished product shall be assembled on site. The installation of the foundation plate of the support frame shall meet the design requirements.

（4） Water heater equipment assembly:

Tubesheet collector is a kind of collector widely used at present. It is used with hot water storage tank and installed obliquely. The glass installation of the collector should be overlapped or frame connected along the water.

2. Installation orientation of the collector: in the northern hemisphere, the best orientation of the collector is due south, and the maximum deviation angle shall not be greater than 15 °.

 

 3. Installation inclination of collector: the best inclination shall be determined according to the following regulations according to the season of use and local latitude:

(1) When it is used in spring, summer and autumn, the inclination angle is set at the local latitude.

(2) When it is only used in summer, the inclination angle is set 10 times smaller than the local latitude °.

 

( 3) When it is used all year round or only in winter, the dip angle is 10 times larger than the local latitude °.

 

 4. Fabrication and installation of directly heated hot water storage tank:

(1) The water supply shall be led to the bottom of the water tank, and the make-up water tank or funnel water distribution mode can be adopted.

(2) The hot water shall flow out from the water tank, and the height of the connecting pipe is generally 50-100 mm lower than that of the upper circulating pipe. In order to ensure the full use of water in the water tank, the outlet pipe from the bottom of the water tank shall be connected in parallel with the upper hot water pipe

(3) The upper circulating pipe is connected to the upper part of the water tank, which is generally about 200 mm lower than the top of the water tank, but it is necessary to ensure that it is submerged below the water surface during normal circulation, and make the ball valve work normally after installation.

(4) The lower circulating pipe is connected from the lower part of the water tank. In order to prevent sediment from entering the collector, the outlet should be more than 50 mm above the bottom of the water tank.

(5) The gradient of the circulating pipe from the upper and lower header of the collector to the hot water tank shall not be less than 0.005.

(6) The water tank shall be equipped with drain pipe, vent pipe, overflow pipe and necessary instrumentation.

(7) The installation of the hot water storage tank shall ensure normal circulation. The bottom of the hot water storage tank shall be higher than the highest point of the collector by more than 200 mm. When the upper and lower headers are set outside the collector, they shall be higher than 600 mm.

（5） Water distribution pipeline installation.

1. Pipeline installation of natural circulation system:

(1) In order to reduce the circulating head loss, the length of the upper and lower circulating pipes and the number of elbows should be shortened as far as possible, and elbows and downstream tees with smooth inner wall and more than 4 times of curvature radius should be used.

(2) The valve should not be set on the pipeline.

(3) When several collectors are installed, the collectors can be connected in parallel, series or mixed, but the circulating flow should be evenly distributed. In order to prevent short circuit and stagnation, the circulating pipeline should be installed symmetrically, and the circulating head loss of each circuit should be balanced.

(4) In order to prevent air blocking and stagnant flow, the installation of circulating pipeline (including upper and lower headers) should be no less than 0.01 gradient to facilitate exhaust. The highest point of pipeline shall be equipped with ventilation pipe or automatic exhaust valve.

(5) A drain valve should be added at the lowest point of the circulating pipeline system to make the water in the system completely drained. A thermometer shall be added at the outlet of each collector.

The mechanical circulation system is suitable for large water heater. The installation requirements are basically the same as that of natural circulation, and the following points should be noted:

(1) The installation of water pump should be able to meet the normal operation at 100 ℃.

(2) The high point of indirect heating system should be added with expansion pipe or expansion water tank.

（6） The installation of hot water supply pipeline system is the same as 1-2.

（7） Pressure test of pipeline system: hydrostatic test shall be conducted before insulation, and the pressure value shall be 1.5 times of the working pressure of pipeline system. The minimum is not less than 0.5MPa.

（8） After the completion of pressure test, the system should be washed or blown until the dirt is completely washed out.

（9） After the installation of the water heater system, the temperature control instrument shall be installed according to the design requirements before the handover.

（10） According to the design requirements, do a good job of anti-corrosion and insulation.

（11） The solar water heater system shall be debugged and operated before handing over. The system shall be filled with water, and the air shall be removed. The circulation pipeline shall be checked for air resistance and stagnation. The mechanical circulation shall be used to check the operation of the water pump and whether the temperature rise of each circuit is balanced. The temperature rise record shall be made. Generally, the temperature rise of water passing through the collector shall be 3 ℃ ~ 5 ℃. After meeting the requirements, go through the handover and acceptance procedures.

5、 Quality standard

（1） Main control items:

The results of hydrostatic test and full water test of hot water storage tank of solar water heater system must meet the design requirements and construction specifications.

Inspection method: check the system test record and water tank full water test record.

2. The solar water heater system must be washed or blown before delivery.

Inspection method: check the washing or blowing records.

（2） General items:

1. The installation of the bracket or base of the hot water storage tank shall be flat and firm, the size and position shall meet the design requirements, and the water tank shall be in close contact with the bracket.

Inspection method: observe and check the design drawing.

2. The painting of water tank shall be well adhered, with uniform film thickness and uniform color, without flowing and pollution.

Test method: observation.

6、 Finished product protection

1. The collector should be protected during riveting and installation to prevent the glass from breaking.

2. The temperature control instrument should be installed before handing over to prevent loss and damage.

When the solar water heater is not used in winter, the system water should be drained.

7、 Problems to be paid attention to

The effect of solar water heater is not good.

1. Correctly adjust the installation orientation and inclination angle of the collector to ensure the best sunshine intensity.

2. Adjust the gradient of the upper and lower circulating pipes and shorten the pipeline to prevent air blocking stagnation and reduce resistance loss.

3. The installation position of solar water heater should avoid the shadow of other buildings to ensure sufficient sunshine intensity.

4. When installing the solar water heater, it should be avoided to be set in the downwind direction of the chimney and other facilities producing smoke and dust, so as to prevent the smoke and dust from polluting the transparent cover and affecting the light transmission.