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[技术] 自己建立太阳能热水系统

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发表于 2014-3-27 13:36:54 | 显示全部楼层 |阅读模式
自己建立太阳能热水系统

自己建立太阳能热水系统

自己建立太阳能热水系统


At the time of writing this 10/03/08. I would estimate that I am spending about £300 a year on hot water. We use this amount for washing and bathing and about another £100 that we use to run our washing machine and dishwasher. A total of about £400 for our family of four living in a three bedroom semi. With the solar hot water system described here I am hoping to save about a half of this. About £200. This I consider a worthwhile saving that will increase year after year as gas and electricity prices continue to rise.
Have had a few questions on these figures. Some people think that £400 is an exaggerated figure for heating water in a year. While a few others say they spend more than this. I think that before you embark on this sort of project it would be a good idea to try to work out how much you actually spend on hot water. You will need to look back over a years electricity and gas/oil bills and add them up. If you do not keep old bills you will have to study your old bank statements. So I have been told about 30% of this total will be your hot water costs. So for example if your total energy costs for a year come to £1500 then for hot water your costs will be £500. You will probably be able to save about 40% to 50% of this amount £200 to £250.
 楼主| 发表于 2014-3-27 13:38:23 | 显示全部楼层
Important disclaimer
It is possible to hurt your self. You can cut, burn, choke, poison, or scald yourself messing about with this. You could also fall from the roof or fall down the ladder with a cable around your neck on to a wooden stake. You could electrocute your self ( with power tools ). Blow lamps can explode and solder flux can give you dermatitis. You could get tetanus or blood poisoning from a splinter or paper cut. You could have an accident on the way to B&Q in the car. So if you follow these instructions its at your own risk. Wear goggles, steel toe cap boots, thick leather gloves, a face mask and hard hat at all times. Use an RCD and proper scaffolding . Never work outside in a thunder storm. Anything you do is your own fault, it's not my fault. I am not your mum. Good Luck see you in the next life.

太阳能热水系统

太阳能热水系统

It's a great idea to have a solar hot water system , but at what cost. Solar hot water has become very big business these days, with gas and electricity prices just going up and up. Many people who are "just enquiring" end up being sold ( often on credit ) systems that are very unlikely to ever recover their capital costs. I believe I can save about £200 a year with this system. If I were to purchase a professionally made,installed and maintained system for say £6000 it would take me about 30 years to recover this cost. This is without taking into account the on going costs of servicing and repairs to over complicated evacuated tube systems. Buying a system on credit will also have to include the cost of credit ( interest ) that is often overlooked. If I would pay £6000 cash up front for a system there is also the cost of lost interest to be factored in. £6000 in a decent savings account will probably earn more money in interest than you can save by using solar to heat your hot water. As we know from past experiences with double glazing, conservatories etc, very few of these companies that are selling expensive solar hot water systems with long guarantees, will be around in five years time. Its got to be a DIY system or no system.
Flat plate vs Evacuated tube solar collectors/panels.
 楼主| 发表于 2014-3-27 13:38:38 | 显示全部楼层
It is claimed that evacuated tube solar collectors are typically more efficient than flat plate collectors. This does not mean that evacuated tubes can produce more hot water, it's just that the panel area can be reduced. You will need a larger flat plate panel than an evacuated tube array to heat the same size water tank, but with either type you will get about the same amount of hot water each year. You can't make your own evacuated tube array. You have to buy from China. Salesmen like evacuated tubes, they are much more **y and need a much more complicated system that is considerably more expensive and needs servicing. Money Money Money. An independent study by the DTI compared a number of different types of system and the panel that produced the most hot water was of the flat plate variety. Tubes are for suckers. Most evacuated tube systems require mains electricity for pumps, valves, controllers etc thus negating any gains over flat plate collectors. These complicated systems will almost certainly come with an annual service contract that will be linked to any warranty.
Send us your quotes. We hear that some big name UK companies are quoting up to £12000 for a solar hot water system. If you have such a quote please send it so I can publish it here.
Quote 1: ( Bournmouth ) Two hour high pressure visit. 1 solar panel, 40 gallon hot water cylinder, pump and box of electronics, £11,500 or £6,400 if ordered within 24 hours.
Quote 2: British Gas claim you can save £85-£350 a year with their system, costing £3600.00. Will take from 10.2 to 42 years to pay for it self ( is nothing goes wrong ).
Quote 3: Solartwin. £3,699 installed or £2,699 DIY.
Quote 3: According to the Energy Saving Trust, the average price for a system is £4800.00.
Quote 4: Whilst visiting an energy display in my area I was quoted up to £10,000 for thermal panels.
Quote 5: British Gas latest. Approximate cost for a system £ 5000.00 inc VAT ( At least 30 year payback).
Quote 6: Tesco £ 4,339  ( At least 25 + payback )    Double Clubcard points.
THE PLAN
 楼主| 发表于 2014-3-27 13:39:42 | 显示全部楼层
I am not claiming any originality for these systems. I have studied many solar hot water web sites and put together what I consider to be the best plan for my needs.

太阳能热水系统

太阳能热水系统

This is about as simple and low cost as you can get. The pump and P/V panel are the only parts liable to give any problems. My money at the moment is on the Charles Austen DL2 pump ( Six weeks delivery unfortunately ), but looks the part, and is what I am using in my system. For this pump you will need a P/V panel rated at about 10 watts. These panels appear to give about half of their rated output. If you buy a panel that is too small like I did, you will then have to buy another one. So get one about 10 watts. If its too small its no good, If its a bit too big you can always damp it down a bit. Put the pump and P/V panel so that you can get to them easily. Important. Pump must be situated where it cant freeze. Also pump must be 150mm to 250mmabove the water level in the expansion tank that supplies your boiler. You must make sure that the pump does not pump if the panel is frozen. Switch it off on cold nights/mornings.
 楼主| 发表于 2014-3-27 13:40:24 | 显示全部楼层

太阳能热水系统

太阳能热水系统

To get the most heat gain from the available Sunshine it is necessary to use some sort of electronic control board and a minimum of two temperature probes. The Solarfriend#1 controller board uses a PIC 16F676 Microcomputer and needs just an 8 to 15 volts DC power supply. The board has a single pole changeover relay that should easily cope with most small pumps. For larger pumps the on board relay could be used to trigger a larger relay. The temperature probes must be situated one on the solar water panel near to the outlet. And the other on the hot water cylinder. Where about's on the cylinder is subject to quite a bit of experimentation. On my system the cylinder probe is under the insulation about 20cm from the top, But I may move this about when I get Time. To begin with I have set the difference adjuster to about 10 degrees. That is to say that the relay only energizes if the panel temperature is 10 degrees above the cylinder temperature. If the panel temperature goes above the difference value the relay energizes for about 5 seconds ( Adjustable ). This will be the pump on time. Then there is an off time about 15 seconds ( adjustable ). The whole thing repeats continually in a cycle. Should the panel temperature fall below 18C the board just idles, using very little current until the temperature rises above 18C. This does away with the worry that the pump will pump into a frozen panel.


 楼主| 发表于 2014-3-27 13:40:55 | 显示全部楼层

太阳能热水系统

太阳能热水系统


太阳能热水系统

太阳能热水系统

Picture above shows Solarfriend #3. This panel uses PIC 16F833 Micro controller and has a wide range of adjustment for difference value 0-20 degrees approximate, on time 0-20 seconds and off time 12-32 seconds aprox. There is also an ( AUTO ) setting. This panel is designed to suit most DIY systems.
 楼主| 发表于 2014-3-27 13:41:19 | 显示全部楼层
FREEZE PROOF ROOF MOUNTED WATER PANEL
To begin with I made a wooden frame from some 95mm x 20mm hardwood. This frame is made so that a sheet 2445mm x 1222mm of exterior grade 10mm plywood will sit inside the frame flush with the bottom edge screwed to wooden strips 40mm x 20mm that are screwed on edge inside the frame. The sheet of plywood you buy dictates how big you make the frame. The outside dimensions of my frame are 2490mm long x 1268mm wide x 95mm deep. This panel is about 3 square meters in size.

太阳能热水系统

太阳能热水系统


太阳能热水系统

太阳能热水系统

 楼主| 发表于 2014-3-27 13:41:45 | 显示全部楼层

太阳能热水系统

太阳能热水系统


太阳能热水系统

太阳能热水系统

 楼主| 发表于 2014-3-27 13:42:11 | 显示全部楼层

太阳能热水系统

太阳能热水系统

The two sheets of 16 swg aluminium that I purchased were just a bit too big to fit inside the frame so it had to be trimmed with tin snips to a final size of 2435mm x 1200mm that was about 20mm smaller than the inside of the frame so as to give a 10mm clearance all around.

太阳能热水系统

太阳能热水系统

 楼主| 发表于 2014-3-27 13:44:11 | 显示全部楼层

太阳能热水系统

太阳能热水系统

The idea is that the 15mm ID 3mm wall silicone tube gets squashed in between the two sheets of ally. So that the tube is not completely closed up I put a strip of 25mm x 10mm ally around the edge of the sheet and 45 ally 10mm x 25mm round spacers on the sheet. These spacers that are on the sheet can be made square from the same ally bar that is around the edge of the sheet. The four corner most spacer are approximately 175mm in from each corner edge, then in a grid 9 across the sheet 105 mm apart then 5 along the sheet 522mm apart.

太阳能热水系统

太阳能热水系统

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