General Questions

Solar energy is the best option for cutting down cost of electricity, continuous load shedding and increase in electricity bills every month. It does not require fuel (Petrol / Diesel / Gas etc), virtually no maintenance. It is very easy to look after. It is green energy and once installed will produce power for years to come. Generally a proper solar system installed in house will return its money back within 5 years and same on commercial place will return the money in 3 years.

Solar energy takes advantage of the sun's rays to generate heat or electricity. It is an infinitely renewable resource and unique for its ability to generate energy in a quiet, clean, and consistent manner. Can't beat the sun for being oh-so-cool!

In layperson terms, photovoltaic cells are comprised of a semiconductor material such as silicon. Added to the silicon are the elements phosphorous and boron which create conductivity within the cell and activate the movement of electrons. The electrons move across the cell when activated by the sunlight's energy into the electrical circuit hooked up to the solar panel.

Off-grid - The term off-grid refers to not being connected to a grid, mainly used in terms of not being connected to the main or national transmission grid in electricity. In electricity off-grid can be stand-alone systems (SHS) or mini-grids typically to provide a smaller community with electricity. Off-grid electrification is an approach to access electricity used in countries and areas with little access to electricity, due to scattered or distant population. It can be any kind of electricity generation. The term off-the-grid (OTG) can refer to living in a self-sufficient manner without reliance on one or more public utilities. On-grid - Grid-connected or grid-tied means If a grid connect system is producing more power than is being consumed, the surplus is fed into the mains power grid. Some electricity companies will meter the electricity fed into the grid by your system and provide a credit on your bill. When the solar cells are not producing power, for example at night, your power is supplied by the mains power grid as usual. The energy retailer charges the usual rate for the power used. Note that there is no provision in Pakistan’s infrastructure to sell back excessive power. Therefore it is always suggested to have battery backup to store extra energy being produced from solar panel. This way all energy harnessed is stored and subsequently utilized.

PWM stands for Pulse Width Modulation. PWM is often used as one method of float charging. Instead of a steady output from the controller, it sends out a series of short charging pulses to the battery - a very rapid "on-off" switch. The controller constantly checks the state of the battery to determine how fast to send pulses, and how long (wide) the pulses will be. In a fully charged battery with no load, it may just "tick" every few seconds and send a short pulse to the battery. In a discharged battery, the pulses would be very long and almost continuous, or the controller may go into "full on" mode. The controller checks the state of charge on the battery between pulses and adjusts itself each time. The downside to PWM is that it can also create interference in radios and TV's due to the sharp pulses that it generates. MPPT (Maximum Power Point Tracking) solar controllers are considerably more elaborate than PWM controllers. The optimum voltage for battery charging changes as the battery's state of charge changes, and the panel's output varies depending on temperature, available sunlight, and more. The MPPT charge controller matches these two voltages and can result in up to 30% more efficient charging. This means a good MPPT solar charge controller can deliver the same level of charge with fewer panels, a tremendous benefit. A MPPT solar panel charge controller can leverage the rest of the system to better performance. However they are relatively expensive.

Both photovoltaic modules and batteries use direct current (DC) power. We need an inverter to change the direct current to alternating current (AC) in order to utilize the power being generated in a home. In order to maximize energy output, it is important to select an inverter with the following characteristics: 1. High efficiency 2. Low standby losses 3. High surge capacity 4. Low harmonic distortion One way of classifying inverters is to distinguish the AC output waveforms - these are pure sine wave and modified sine wave. All grid tied inverters are pure sine (true sine) inverters, hence the grid, by nature, is a pure sine wave electricity source. The importance of pure sine wave or modified sine wave inverters may be apparent especially for off grid applications such as RV, boat or cabins. Off grid inverters are used for connecting a battery source or a solar PV system to an AC load such as a home appliance, a laptop charger, a TV. Pure sine wave inverters are used to operate sensitive electronic devices that require high quality waveform with little harmonic distortion. In addition, they have high surge capacity which means they are able to exceed their rated wattage for a limited time. This enables power motors to start easily which can draw up to seven times their rated wattage during startup. Virtually any electronic device will operate with the output from a pure sine wave inverter. Modified sine wave inverters (modified square wave or step wave) approximate a pure sine waveform. Modified sine wave inverters are designed to satisfy the efficiency requirements of the photovoltaic system while being less expensive than pure sine waveform inverters. These inverters are capable of operating a wide variety of loads; electronic and household items including but not limited to TV, VCR, and satellite receiver, computers, and printers.

The array size you need depends on your average electrical usage, climate, roof angle, shading problems and many other factors. To approximate the array size you need, multiply your average daily electrical demand in kilowatt-hours by 0.25. The result is the approximate size of solar array, in kilowatts, needed to meet your electrical demand.

With no moving parts and made of very inert materials, our solar modules are tough. Most of the related system components should also last for many years without problems. The batteries in our residential system may need replacement in five to 10 years.

While both types of solar systems capture energy from the sun, solar photovoltaic systems use photovoltaic panels to produce electricity. Solar hot water, or thermal, systems capture sunlight to heat water for domestic use, to heat a swimming pool, or for a radiant heating system.

Solar hot water systems, broadly termed solar thermal systems, use the sun's energy to heat water. Solar hot water systems can be used to heat a hot water tank or to warm a home's radiant heating system. Swimming pools and hot tubs use a modified solar hot water system for heating water.

Planning, configuring, and doing any custom ordering for your solar energy system can take up to a few weeks. However, the installation process itself can typically be completed in only a few days time, in many cases even less.

Other Questions

GP Tech Energy is highly professional company. Our main aim is to design high quality yet simple systems. We provide custom design to meet requirement of client individually. We offer most suitable solutions and maintain the high quality of hardware. We visit each location and prepare the most suitable solution of our client needs.

Generally a careful calculation shows that installation cost returns back as following: 1. Residential use – 5 years 2. Commercial use - 3 years

Solar photovoltaic panels require little maintenance – no need to wash or dust. It is, however, important to place panels where they will remain clear of shade and debris. Thus you will have to wipe them off if too much snow / dust or leaves fall on them.

Many companies in Pakistan advertise GRID TIED systems. But unfortunately the infrastructure in Pakistan does not allow having GRID TIED installations. GRID Tied installations are referred as selling back extra electricity produced by Solar System to National Grid.

Battery back-up is having lot of advantages as; 1. Extra energy produced is not waste but stored in batteries. 2. Stored energy can be used if panel output is less than consumption due to heavy clouds 3. Stored energy can be used during the night if required. However, there are some disadvantages also; 1. Cost of installation 2. Life of batteries 3. Hazards associated with batteries GP Tech Energy provides most suitable and economical solution. We plan / design and install systems to meet clients need and provide valuable suggestions to optimize cost and benefits.

In bright sunlight, a square foot of a conventional photovoltaic panel will yield 10 watts of power. That's a helpful rule of thumb for calculating a rough estimate of how much area you might need. For example, a 1000 watt system may need 100 – 200 square feet of area, depending on the type of PV module used.

The size of the photovoltaic system is correlated to your home's energy-use needs, available space for a system, and overall costs for the system components and installation. We can visit your premises and provide all necessary details as part of our services.

Unfortunately shading a photovoltaic system dramatically decreases its output. Just shading the bottom row of wafers alone amounts to an 80% reduction in efficiency. So above all, don't shade your array!

No. Sunlight must be present for your solar modules to produce power. At night, you draw power from your utility.

Yes, though they produce less electricity. Under a light overcast sky, panels might produce about half as much as under full sun.

Because of the wiring design of a solar module, all of the individual solar cells on a module must receive full sunlight for the module to work properly. If any portion of the module is shaded, the entire module power output-even those sections still exposed to sunlight-is lowered.

We offer various types of solar residential systems. 1. System powers your home during daylight hours but does not provide power in an outage, even on a sunny day. 2. System powers your home during daylight hours but also has a battery backup designed to provide power to your home's critical loads during an outage, day or night. 3. System to power your home partially with battery backup. This will provide power to particular appliances during power outage day and night. 4. System with combination of charging from grid power and solar in the same time. This solution is economical as number of installed panel and batteries are less.

You should go years without problems. The batteries in our residential system may need replacement every 3-5 years. We recommend that the installer do a system check once a year, just to make sure everything is performing, as it should.

In the event of problem GP Tech Energy will visit the site as soon as possible and clear all issues under warrantee. However, a separate service contract is required if our client feels to check the installations and trouble shoot them.

Yes, if you install a system to provide power for whole home, you can be totally independent from WAPDA. However, we don’t recommend using air conditioner on Solar power. This makes your system less economical.

Yes, many Companies may provide cheaper solution, however they often provide solution with low quality and/or unsuitable hardware. GP Tech Energy not only provides solutions but also explains the hardware being offered with its benefits. GP Tech Energy is committed for quality and cost. We don’t want only SALES, but we want SALES with SATISFACTION of client. Our product / solution will make sure that our client gets best possible system for his value able money.