Frequently Asked Questions (SPV)


PV technology produces electricity directly from electrons freed by the interaction of sunlight with a solar panel made of semiconductor material. The power provided is direct current (DC) Electricity. The basic building block is known as a cell. Many cells put together are known as a module, and many modules assembled together form an array.

Monocrystalline solar panels are made up of single crystal wafer cells. These require a smaller surface area which is great when you have limited space.

Multicrystalline solar panels are made from multifaceted silicon crystal. These usually require a larger surface area as they are less efficient when converting the sun’s rays. New technology is diminishing the performance gap between monocrystalline and multicrystalline solar panels.

Thin film solar panels are created by applying a thin layer of material with photoelectric properties directly onto flexible materials. This process requires much less silicon. Thin film panels are less efficient than crystalline solar panels and therefore require a large surface area. The thin film also degrades faster over time than crystalline panels. Thin film technology is marketed as having the ability to perform better in cloudy conditions, but they aren’t proven to generate more kWh’s in a year than crystalline panels.

A PV system is made up of different components. These include PV modules (groups of PV cells), Which are commonly called PV panels; one or more batteries; a charge regulator or controller for a stand-alone system; an inverter for a utility-grid-connected system and when alternating current (AC) rather than direct current (DC) is required; wiring; and mounting hardware or a framework.

Majority of electrical equipment’s used for domestic/commercial/Industrial purposes are of AC system. So, it is necessary to convert solar power generated at DC system to AC system. An inverter will convert DC to AC system. Kotak Solar makes use of MPPT range of inverters for it Solar Power System.

Grid-connected photovoltaic power system, or Grid-connected PV system is an electricity generating solar PV system that is connected to the utility grid. A grid-connected PV system consists of solar panels, one or several inverters, a power conditioning unit and grid connection equipment. They range from small residential and commercial rooftop systems to large utility-scale solar power stations. Unlike stand-alone power systems, a grid-connected system rarely includes an integrated battery solution, as they are still very expensive. When conditions are right, the grid-connected PV system supplies the excess power, beyond consumption by the connected load, to the utility grid.

  1. Grid Connected – These systems have no storage other than the grid itself. Any excess electricity is fed back into the grid. At night, or during times of intense cloud cover, the building draws on power from the grid.
  2. Hybrid (Grid tied with storage) – These systems are grid connected, but also have some storage capacity by way of a small battery bank. They provide some measure of continuity when the grid goes down at the same time as there is not sufficient solar input. This can be installed on your shadow free Rooftop.
  3. Off-grid – These systems are suited to remote locations where a grid connection is not available. The battery bank is sized to provide a certain number of days of storage and the building draws on this store during the night or during days of intense cloud cover.

Solar PV systems can be used to power your entire home’s electrical systems. Including lights, cooling systems, and appliances.

PV systems can be blended into virtually every conceivable structure for commercial buildings for power generation. You will find PV being used outdoors for security lighting as well as in structures that serve as covers for parking lots and bus shelters, generating power at the same time.

Identifying the Solar Power plant size for your domestic or commercial premises depends on the following factors:

  • Wattage of appliances to be run on Solar
  • Monthly energy consumption from these appliances
  • Energy Backup or Days of Autonomy required
  • Roof space available for plant setup

Based on these factors, the power plant sizing can be accordingly done at your end.

There are 2 kinds of Financing mechanisms that are usually discussed – Recourse Financing and Non-Recourse Financing. Recourse Financing requires collaterals and other extensive guarantees from the Solar developer who wishes to avail loan. Non-Recourse Financing, on the other hand, does not require any additional collateral as the Asset or Power Plant itself is the collateral in this case. Recourse Financing is the prevalent mechanism in India currently owing to lack of confidence of banks in the Power and Solar Power sector. The typical Debt-Equity Ratio (Loan to Investment Ratio) for Solar Power plants is 70:30. And the typical collaterals required for a 70% project cost loan could be in the range of 40-60% project cost. This, however, varies from bank to bank as each bank has its own risk perception/mitigation strategy, exposure targets to various sectors and Non-Performing Asset (NPA) limits.

Net meter (bi-directional meter) is having provision to record energy imported from the grid meet the load and energy exported to the grid after self-consumption. Both energy import and export records in the net-meter. The difference between Export and Import readings is the actual energy consumed/delivered.

The SPV Panels will be normally having 25 years of limited warranty of power generation.

Solar panels are flat panels of photovoltaic arrays mounted on a roof or a pole to capture the sun’s rays. Building integrated photovoltaic materials are PV arrays that are integrated into the building material itself, primarily windows, roof tiles, or walls. Solar panels work well for retrofits or remodels while BIPV are appropriate for new construction or a major renovation.

The grid connected SRTPV system of 1 kW peak power capacity requires about 100 sq.ft. shadow free area on the rooftop.

For every KW peak SPV system installed on a South facing roof, the system will generate 4 to 5 units per day. However, the energy generation depends upon the weather conditions and reduces by around 25% for an East or West facing roof.

The cost of the SRTPV system depends on the make of the system used, however, the approximate cost of PV systems varies between Rs.70, 000 to Rs.1, 00,000 per kWp.

Solar PV panels manufactured as per National and International standards are robust and can withstand the normal stresses subjected by nature.

We, Kotak Solar design it solar PV Module specifically for harsh environments and have taken special care to create a robust system that will withstand the elements. Our Solar PV Modules are certified by TUV Rheinland, Japan for IEC 61215(Performance), IEC 61730 (Safety Class 2, Fire Test passed, part 1 & 2), IEC 61701 (Salt Mist Corrosion test to with stand the harsh environment of Coastal area).

Yes, Ministry of New Renewable Energy (MNRE), Ministry of Power, GOI will grant subsidy. For further assistance please visit

A Solar Water Heater is a device which provides hot water for bathing, washing, cleaning, etc. using solar energy. It is generally installed at the terrace or where sunlight is available and heats water during day time which is stored in an insulated storage tank for use when required including mornings.

A Solar Water Heater comprises of array of solar collector/s to collect solar energy and an insulated tank to store hot water. Both are connected to each other. During the day time, water in solar collectors gets heated which is either pumped or flown automatically on Thermosyphon principle to the storage tank. Hot water then stored in the tank can be used for various applications.

Two types of Solar Water Heaters are available; one based on flat plate collectors and the other based on evacuated tube collectors. Flat plate collector (FPC) based systems are of metallic type and have longer life as compared to Evacuated tube collector (ETC) based system because ETCs are made of glass which are of fragile in nature. Both these systems are available with and without heat exchanger. They can also work with and without pump. Systems without pump are known as thermosyphon systems and those with pump are known as forced circulation systems.

ETC based systems are cheaper than FPC based system. They perform better in colder regions and avoid freezing problem during sub-zero temperature. FPC based systems also perform good with anti-freeze solution at sub zero temperature but their cost increases. In other regions, both perform equally good. Systems working on thermosyphon principle are simple and relatively inexpensive. They are suitable for domestic and small institutional applications, provided water quality is good and it doesn’t have large chlorine contents. Forced circulation systems are generally preferred in industries or large establishments. At places where water is hard and have larger chlorine content, if FPC based system is being installed, it must be with heat exchanger as it will avoid scale deposition in copper tubes of solar collectors which can block the flow of water as well reduce its thermal performance. ETC based systems will not block the flow of water but its performance may go down due to deposition of salt contents on inner surface of glass tubes, which could be cleaned easily once in a year or so.

Cost of solar water heater depends on size and type of system installed. Smallest size of a system is 100 liter per day, which means that it can deliver 100 lietrs of hot water in a day at 60 C. A 100 lpd capacity system is sufficient for a family of 3-4 members and it may cost Rs. 18,000 to Rs.22,000 in planes depending on the type of system. In hilly & N-E region, the cost may be 15 to 20% more. The system cost does not include the cost of cold water tank, & its stand which is required if overhead tank is not installed in a house/ building. Cost of hot water insulated pipe line also, may be extra depending on bathroom distance from the Solar Water Heater. Additional cost towards all these components may increase by 5 to 10%. The cost, however, does not increase linearly with increase in capacity, rather it comes down proportionately as we go for higher capacity system.

Yes, the Government provides subsidy to the extent of 30 to 60% to different category of users and States subject to certain benchmarks as per below: Pls visit for more details about Subsidy related matters.

General category states for all types of beneficiaries: 30% capital subsidy orloan at 5% interest on 80% of the benchmark cost . At present subsidy is Stopped.

The system can be installed at net of subsidy by following ways:

Domestic Systems
Through State Nodal Agency – Contact respective state nodal agency in your state ( list with phone no. given on MNRE website) who will visit the site, provide information on cost, size & other details of system required and get it installed at net of government subsidy through some manufacturers.

Through Accredited Channel Partners of MNRE (List available at MNRE website) – Contact any of them and get the system directly installed from him at net of subsidy.

Institutional Systems
Through State Nodal Agency – In same fashion as above by inviting tenders and placing order to selected manufacturer

Through DGS&D rates – Details available on DGS&D website

Through Accredited Channel Partners – In same fashion as above

A 100 litre per day capacity system suitable for 3-4 people can save upto 1500 units of electricity in a year, depending on hot water used. It can also save around 140 litres of diesel in an establishment using oil fired boiler besides reducing green house gas emissions in the atmosphere. Higher capacity systems will save higher amount of electricity/fuel oil besides reducing higher amount of GHG emissions. Electricity is expensive and is not available due to power cuts in many areas when required for heating water. Solar Water Heater, since it stores hot water in an insulated tank, provides water all the time when required. Fuel oil is also expensive and creates pollution. Storing the fuel oil for long term use in commercial establishments is another problem.

The table below gives approximate likely electricity and money savings for a typical 100 liters per day system located in different parts of the country. Northern Region Eastern Region Southern Region* Western Region*
Expected no. of days of use of hot water per year 200 days 300 days 250 days

About 60 to 80º C. The rise in temperature depends on: Solar radiation, weather conditions & number of solar collectors

It is preferable to install the system at your roof top where the solar radiations are freely available. However, it could be installed in the Balcony, Terrace and open ground. Smaller systems may also be installed at the window by providing a suitable structure to support the system.

The capacity of a solar hot water system is specified is LPD. It is a short form for Litres Per Day. The intensity of Solar radiation varies throughout the day, hence capacity cannot be specified in terms of hourly output.

There is no need to discard your Geyser. It can be used in combination with your new SWH. The only thing that you need to do is to connect the out let of your SWH to the inlet of your existing geyser. The temperature of the water coming out of SWH can also be elevated through the electric geyser, if needed.

On cloudy days also, if it is for a day or two, you still get warm water as water gets heated due to diffused radiation available in the atmosphere.The system, however, is either connected to an electric geyser in the house or an electrical back-up is provided in the storage tank of the system which is switched on when water is not sufficiently hot. So, you get hot water all the time even on rainy days.

Yes. The cold water is heated during the day & it is stored in an specially insulated storage tank all night, this insulation prevents the water from losing heat, so that you have piping hot water the next morning.

Yes ! The advantage of the solar hot water geyser is that you get hot water any time of the day or night, and irrespective of the fact whether there is electricity or not! This is true, but is limited to system capacity- the maximum quantity of hot water that can be utilised in a day will depend on the system capacity. If you withdraw more water than the rated capacity, then the water might not be hot enough.

A separate insulated pipe is required from Solar Water Heater Tank to Utility Point. In case of G. I. Pipe the temperature falls due to heat loss during the flow.


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