Home Products System Installation Service Order Hornor Contact
 Product Categories
Non-pressurized Solar Water Heater
Integrate Pressurized Solar Water Heater
Solar Collectors
Split Solar Water Heaters
Flat plate solar water heater
Vacuum Tubes
Spare parts
 Product Search




 Q/A
  Frequently Asked Questions&Answers!
  Q/A
Frequently Asked Questions&Answers!
Time: 2010-6-11 17:49:09  Read: 1989

                  1. Is solar water heating a viable alternative to gas or
                  electricity?
                  2. How long will it take to recoup my investment?
                  3. Can JiShen solar collectors be used in cold conditions?
                  4. What happens if one of the tubes is broken?
                  5. Will water be heated on a cloudy day?
                  6. Can I use a solar collector with my existing hot water
                  system?
                  7. Are the solar collectors noticeable on the roof?
                  8. Can JiShen solar collector be mounted on a flat surface?
                  9. How do I protect my solar system during subzero
                  temperatures?
                  10. Will the solar collector be a fire hazard during hot, dry
                  weather?
                  11. Can the solar collector heat water to a high enough
                  temperature?
                  12. What maintenance of the solar collectors is required?
                  13. Can JiShen solar collectors be used for a large scale hot
                  water production?
                  14. Can I heat my swimming pool using an JiShen solar
                  collector?
                  15. Are solar tube collectors more efficient than flat plate
                  collectors?
                  16. Which collector is the best value for money?
                  17. What is the solar radiation (Insolation) level where I
                  live?
                  18. How do I calculate what size collector I require?
                  19. Where can I purchase an JiShen solar collector?
                  20. Can JiShen solar collectors be used in a drain back
                  configuration?
                   
                  1. Is solar water heating a viable alternative to gas or
                  electricity?
                  Solar should not be seen as an alternative to gas or
                  electricity, but rather a supplement. Solar cannot totally
                  replace the need for gas or electric heating as there are
                  sometimes days when there is little sunlight. When averaged
                  over a year, a correctly sized solar system can provide
                  60%-70% of a household¨s hot water needs. Providing more than
                  this is unadvisable, as too much heat will be produced in the
                  summer. The hot water system can easily be automated so hot
                  water is guaranteed regardless of sunlight levels.
                   
                  2. How long will it take to recoup my investment?
                  JiShen solar collectors are much more affordable than many
                  other solar hot water heaters. For a household of 4, the price
                  of a full system may not be too much more than a new electric
                  or gas system. Depending on you location (solar levels) and
                  current hot water usage the annual electricity or gas saving
                  will differ. However in a normal household that spends 25% of
                  its electricity bill on hot water heating, the full cost of
                  the purchase may be recouped as quickly as 4-5 years in
                  reduced bills. You will definitely make considerable savings
                  during the life of the solar hot water heater.
                   
                  3. Can JiShen solar collectors be used in cold conditions?
                  Yes. JiShen collectors can be used in temperatures as low as
                  -30oC, although performance is greatly reduced in such extreme
                  conditions. Good heat output is still achieved in mild
                  sub-zero conditions.
                   
                  4. What happens if one of the solar tubes is broken?
                  Firstly, tubes are very strong and not easily broken, but if
                  the worst should happen, solar tubes can be replaced very
                  easily. They are inexpensive and available though your local 
                  JiShen distributor. The JiShen solar collectors can operate
                  with several broken tubes, but the efficiency will be reduced,
                  so it is recommended that broken tubes be replaced
immediately.
                   
                  5. Will water be heated on a cloudy day?
                  Yes. Although the heat output of the solar collector is
                  reduced on overcast days it will still be able to provide
                  heating. If it is a heavily clouded day or raining, then more
                  gas or electric boosting may be required to maintain water at
                  the required temperature. This system will be automated so you
                  don¨t have to worry about running out of hot water on a rainy
                  day.
                   
                  6. Can I use a solar collector with my existing hot water
                  system?
                  Normally yes. Simple retrofit valves can often be used to
                  allow solar to connect to your existing cold water inlet. If
                  your tank cannot accept the solar input directly an additional
                  storage tank can be installed to pre-heat the cold water prior
                  to entering the existing tank.
                   
                  7. Are the solar collectors noticeable on the roof?
                  If only the collector is mounted on the roof it should blend
                  into the roof design quite well.JiShen solar collectors are
                  very thin and can be flush mounted on a roof. From a distance
                  they look somewhat like a skylight. You may have to check with
                  your local council regarding building restrictions when
                  installing your solar collector. Click here to view
                  installation photos.
                   
                  8. Can JiShen solar collectors be mounted on a flat surface?
                  Yes they may be mounted on a flat roof or on the ground by
                  using a stainless steel Flat Roof Frame. The collector should
                  be installed at a minimum of 20o angle to ensure optimal heat
                  pipe operation.
                   
                  9. How do I protect my solar system during subzero
                  temperatures?
                  If you have a system that is operating in areas with subzero
                  temperatures then freeze protection must be implemented. The
                  easiest means of preventing freezing is to use a controller
                  with a low temperatures setting, so when the manifold
                  temperature drops below a certain pre-set temperature
                  (5oC/40oF), the pump will circulate, warming the collector
                  with water from the bottom of the storage tank. The pump will
                  not run continually, just periodically, the frequency of which
                  will depend on the outside temperature. In extremely cold
                  areas, a closed loop using a glycol/water mix may be
                  appropriate.
                   
                  10. Will the JiShen solar collector be a fire hazard during
                  hot, dry weather?
                  No. The JiShen solar collector¨s components are all high
                  temperature rated and non-flammable so even during strong
                  sunlight with the circulation pump turned off (stagnation),
                  the system will not catch alight or give off any sparks. The
                  majority of the solar collector¨s components are stainless
                  steel, aluminum, glass or glass wool. The manifold outlet
                  should be fitted with a temperature relief valve, which will
                  prevent the manifold temperature from exceeding 99oC / 212oF.
                   
                  11. Can the JiShen solar collector heat water to a high enough
                  temperature?
                  Yes, in good weather the JiShen solar collector can bring
                  water to boiling point. Generally this is not necessary and so
                  the system should be designed to provide a daily temperature
                  rise of around 25-30oC (45-54oF) in the summer. Sizing a
                  domestic system that can bring the cold water up to 60oC/141oF
                  in a single day is not logical, because if hot water is not
                  used for one day, the following day the system will be boiling
                  and dumping hot water via the temperature relief valve. This
                  is both a waste of energy and water! Please sensibly size
                  solar water heating system to ensure optimal performance and
                  minimal wastage of water.
                   
                  12. What maintenance of the solar collector is required?
                  Under normal circumstances no maintenance of the system is
                  required. Due to the shape of the tubes regular rainfall and
                  wind should keep the tubes clean. Should a tube even be broken
                  it should be replaced. This, however, is an inexpensive and
                  easy job. Any "handy" person can install a new tube (while
                  adhering to local health and safety regulations). JiShen solar
                  collectors can operate with several broken tubes; however the
                  efficiency will be reduced slightly.
                   
                  13. Can JiShen solar collectors be used for a large scale hot
                  water production?
                  Yes. JiShen solar collectors can be connected in series or
                  parallel to provide large scale hot water production for
                  commercial settings such as a school, hotel or office
                  building. There is really no limit to the size of the system,
                  however collectors must be installed in banks of no more than
                  150 tubes (in series), otherwise the water may boil.
                   
                  14. Can I heat my swimming pool or spa using an JiShen solar
                  collector?
                  JiShen collectors are high temperature collectors, and are
                  therefore ideal for spas, as the volume of water is small and
                  temperature requirements high. For swimming pools, however,
                  the volume of water is large and the temperature rise required
                  is only several degrees. The cost of heating a pool using
                  solar tube collectors (for domestic purposes) may be
                  prohibitively high. For large scale swimming pools, however,
                  MAXSUN collectors may be an extremely viable supplement to gas
                  or electricity.
                   
                  15. Are solar tube collectors more efficient than flat plate
                  collectors?
                  When comparing peak efficiency levels it may seem that there
                  is little difference between flat plate and evacuated tubes,
                  in fact flat plate may actually be higher, but this is during
                  minimal heat loss conditions. When averaged over a year
                  evacuated tube collector have a clear advantage. The key
                  points are:
                  1. Due to the cylindrical shape of the evacuated tube, the
                  solar tubes are able to passively track the sun throughout the
                  day. Flat plate collector only provides peak energy output at
                  midday when the sun is perpendicular to the collector¨s
                  surface. To learn more about IAM and performance click here. 
                  2. Air is evacuated from the solar tube to form a vacuum. This
                  greatly reduces conductive and convective heat loss from the
                  interior of the tube. As a result wind and cold temperatures
                  have less effect on the efficiency of the evacuated tube
                  collector. 
                  3. JiShen solar collectors can often be used in subzero
                  temperatures without the system sustaining damage. Flat plate
                  systems often require expensive and complicated "antifreeze"
                  systems to be installed.
                  4. Evacuated tubes are strong, long lasting, and should one be
                  broken, inexpensive and easy to replace. If a flat plate
                  collector panel is damaged the whole panel must be replaced. 
                  5. Due to the high efficiency absorption of solar radiation
                  even during overcast conditions, combined with excellent
                  isolative properties of the solar tube, solar tube collectors
                  can heat water all year round (backup from gas and electricity
                  is still required). 
                  6. Due to the various advantages of evacuated tube collector
                  over flat plate collectors, a smaller collector can be used to
                  provide the same heating performance. For example, a standard
                  household of 4-5 people would usually require a 250-300L water
                  storage tank. Depending on your location, only 30 evacuated
                  tubes would be required to provide all summer hot water needs
                  and a large percentage in other seasons. 
                  7. Flat plate solar collectors can produce similar heat output
                  to evacuated tube collectors, but generally only during hot,
                  sunny conditions. When averaged over an entire year, evacuated
                  tube collector heat output per net m2 of absorber area, is
                  between 25% to 40% greater that a flat plate collector.
                   
                  16. Which collector is the best value for money?
                  Rather than looking at just peak efficiency levels when
                  comparing solar collectors, cost per unit of energy produced
                  is much more logical. For example: Although collector A may be
                  20% more efficient than collector B, if collector A is 30%
                  more expensive, then in fact collector B may be a better
                  choice, as per kWh of energy produced per day it is cheaper.
                  When payback time is of concern, not only price per kWh of the
                  product is important, but also of the end system. In this
                  regard JiShen solar collectors provides a further advantage as 
                  JiShen solar collectors are very easy to install, and that can
                  make a huge difference in terms of total install costs.
                  For more information comparing collector performance please
                  click here.
                   
                  17. What is the Solar Radiation (Insolation) level where I
                  live?
                  Click here to learn more about Insolation, and to find out
                  values for your region.
                   
                  18. How do I calculate what size collector I require?
                  Please click here to visit the collector sizing page.
                   
                  19. Where can I purchase an JiShen solar collector?
                  JiShen solar collectors are available through an official
                  distribution network.
                  Click here to find your closest JiShen agent.
                   
                  20. Can JiShen solar collectors be used in a drain back
                  configuration?
                  Yes. The end port version of the JiShen solar collector is
                  well suited to drain back use. The question is often asked if
                  the solar collector will be damaged when the pump turns off
                  and the system stagnates in good sun - no it won¨t, as the
                  collectors is designed to withstand stagnation. What must be
                  considered though is the insulation used on the piping close
                  to the collectors, as this must be able to withstand
                  stagnation temperatures.

Copyright @ 2008 www.jishensolar.com All Rights Reserved
Haining Jishen Solar Energy Technology Co.,ltd
Admin Enter