Blog – Proximate Solar

Solar Photovoltaics (PV) Basics

Photovoltaic’ is a marriage of two words: ‘photo’, meaning light, and ‘voltaic’, meaning electricity. Photovoltaic panels form part of a solar PV system, creating energy from sunlight.

Solar Cells

Solar cells are the basic building blocks of a PV system and consist of semiconductor materials mainly made out of silicon. When sunlight is absorbed by these materials, the solar energy knocks electrons loose from their atoms. This phenomenon is called the “photoelectric effect.” These free electrons then travel into a circuit built into the solar cell to form electrical current. Only sunlight of certain wavelengths will work efficiently to create electricity. PV systems can still produce electricity on cloudy days, but not as much as on a sunny day. The performance of a solar (or PV) cell is measured in terms of its efficiency at converting sunlight into electricity. There are a variety of solar cell materials available, which vary in conversion efficiency.

Solar Modules

A photovoltaic module is an array of photovoltaic cells pre-arranged on a single mounting mold. The type of module is therefore determined by the cells that compose the nodule itself. There are three common cell technologies namely monochrystalline,polycrystallnine and multicrystalline

Basic Solar PV System components

Component	Purpose
PV Module	Array of photovoltaic cells pre-arranged on a single mounting mold
Inverter	Used to convert DC electricity produced by solar panels to AC electricity used by appliances
Charge Controller	Regulates battery voltage and ensures that batteries are charged properly.
Battery	Used to chemically store direct current (DC) electrical energy in a PV System
LED Lights	LED lights are energy efficient bulbs the latest technology in lighting and offer a great alternative in replacing conventional lights
Balance of System (BOS) components	Components that move energy produced by solar panels through the conversion system which in turn produces AC, e.g. cables, switches

Overview of Energy Efficiency

Before installing a Solar Photovoltaic (PV) system, it is critical that we are aware of what our clients’ electricity consumption is as well as potential opportunities for energy saving. This is due to the fact that we need to provide our clients with a system that will cater for their requirements and not leave them frustrated because the system generates less power than they actually consume. An electrical energy audit will provide our clients with concise daily statistics of their electricity consumption. This is measured at various intervals during the day and a comprehensive report is compiled which demonstrates their consumption.The report allows us to visually see when most of their electricity is being consumed. Knowing their daily electricity consumption allows them to make changes within their homes or offices to reduce their electricity usage, thereby offering them cost-savings through initiatives such as:

Replacement of conventional light bulbs with energy saving bulbs
Installation of meters to visualize and control of the own consumption
Switching off lights and appliances when not needed
Installation of solar water heating systems
Installation of occupancy sensors in buildings

Solar Water Pumping Overview

Introduction

One of the simplest and most economical uses of solar energy is for pumping water. With advances in pumps and pump controllers, solar water-pumping systems have become fairly easy to install, operate, and maintain. If you live beyond the reach of the grid, have a remote pumping need, or need to cut costs on applications like irrigation, livestock watering, fish farming or water supply in remote locations such villages, schools, hospitals, farm houses and swimming pools, then a solar-electric pump system can be a solution that is reliable and sustainable.

Technology

Solar water pumping systems require site assessments and design before the system components are purchased and installed. Each component must be carefully matched to the others, and to the load, so proper planning is essential, the results will be an efficient, reliable system that will be functioning for years to come. The pumps provide individual solutions to water problems where conventional water supply systems fail or simply cannot reach. Solar panel powered pumps are used to pump groundwater or surface water to a reservoir which feeds domestic outlets. Compared to the use of a diesel or electricity-powered pump, the initial capital cost of a solar-powered system is high but the running and maintenance costs are low since there is no fuel or electric bill to pay for. The life cycle cost is lower because you can save substantially on reduced maintenance cost with no energy costs. A reservoir is used to provide water when there is no sunshine to power the system and should have the capacity to provide up to 5 days’ water consumption, depending on climatic conditions.

Advantages

Solar Water pumping systems have the advantages of a long life span (up to 25 years), easy installation, no maintenance, high efficiency, low lifecycle cost, quiet operation and environmentally friendliness.

Types of Solar Panels

The use of solar energy has an advantage over conventional electricity because it is a cleaner and much cheaper source of energy. Solar panels are an essential component of a home solar power system because they capture the sunlight and generate electricity. Various types of solar panels offer different services and are necessary for different situations. If you are interested in knowing about types of solar panels, you can stick to us. Let us crack it all together.

Types of solar panels

There are different types of solar panels. A specific type of solar panel catered well to your problems according to desired system characteristics and the particular characteristics of your property. So to make a good selection of solar panels, you must be aware of the different types. The most important and widely used types of solar panels are mentioned as under:

 Mono-crystalline
 Poly-crystalline

Both solar panel types have their advantages if correctly used. So, you must make an appropriate selection before making a final decision.

 Mono-crystalline: These are the type of solar panels that comprise mono-crystalline solar cells. The cells are composed of silicon ingots. The cylindrical silicon is sliced into various wafer-forming cells. These circular wafers are wire cut to an octagonal-shaped wafer for extra efficiency. The cells possess a uniform color. They are coated with silicon nitride to increase absorption and reduce reflection.

 Poly-crystalline: Multi-crystalline or poly-crystalline solar panels are all types of solar panels consisting of various silicon crystals in one photovoltaic cell. Multiple fragments of silicone are joined together to form these wafers. They have a surface looking like a mosaic. They have a much higher temperature coefficient than that of mono-crystalline panels.

Solar Water Heating Principles

untitled-2 A solar water heating system consists of the components such as collectors, storage tank, pumps, water/heat transfer fluid, heat exchanges and controllers. The sun radiates energy in the form of heat and light. The collector, when exposed to sun, absorbs most of the heat and the water or heat transfer fluid gets heated up. As a result there is rise in temperature of the water/heat transfer fluid by way of conduction. The collector also loses heat to the by convection and radiation.

By controlling the exchange of heat between the collector and the water/heat transfer fluid, through conduction or convection, it would be considered as a desirable heat exchange. The solar collector tried to increase this desirable heat exchange and reduce the undesirable heat loss to air, atmosphere or other materials in contact. Solar water heating uses both the direct solar radiation that comes directly from the sun and diffused solar radiation that is scattered by the atmosphere.

There are two types of solar water heating systems: active, which have circulating pumps and controls, and passive, which don’t. Most solar water heaters require a well-insulated storage tank. Solar storage tanks have an additional outlet and inlet connected to and from the collector.

Though the initial investment for a solar water heater is high compared to available conventional geysers, the return on investment has become increasingly attractive with the increase in prices of conventional energy. Solar water heating is also an environmentally friendly technology that contributes towards reduction in emissions.

Stand Alone vs. Grid Tied PV systems

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A Solar Photovoltaic (PV) system is able to supply electrical energy to loads by directly converting solar energy through the photovoltaic effect. The system structure is very flexible. PV modules are the main building blocks and can be arranged into arrays to obtain different levels of power production. Other components include the charge controller, battery bank, Inverter and balance of system components. The system is designed taking into consideration the energy needs or loads for a particular application. The two major classes of PV systems are:

The system includes all the elements necessary elements to supply AC appliances in a household or commercial application. A diesel generator may be considered to enhance the system reliability but is not compulsory. The number of components in the system will depend on the type of load that is being served.

Grid Tied PV Systems are directly coupled to the electrical distribution network and may not require battery storage as shown on the diagram below. Electrical energy is either sold or purchased from the electric utility company depending on the energy load patterns and the solar energy resource variation during the day. An inverter is needed to convert DC to AC.

There are many benefits that could be obtained from grid-tied PV systems instead of standalone systems such as less balance of system components needed, eliminates the need for energy storage and takes advantage of existing electrical infrastructure