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With accurate load calculations and today's technology, owning and operating your own “power company” can be a rewarding experience. As with the big utility companies, you must determine the demand for electricity, but in this case the demand begins and ends with you. So the real question is, how much power are you expecting to demand from your own power company, and how can you generate this power in a cost-effective manner? In the following pages you will find a generalized approach to answering these questions about your prospective power company, which could more appropriately be called a Renewable Energy (R-E) system. Effective planning requires that you consider your home (or other application) as a whole— that is, as an interrelated system. In this way you can look at and maximize all opportunities to achieve the greatest degree of energy efficiency possible for your situation, even if you are working with a pre-existing structure. A well-designed system need not compromise the convenience and comfort typically associated with conventional American houses. How is this possible? Smart design, materials, and technology do the job: compact fluorescent lighting and efficient refrigerators, for example, in addition to such factors as the amount of insulation, the placement and type of windows, and the layout of the structure. A well-designed renewable energy system is your best investment. The payback period can be remarkably short with accurate planning and the right technology. The soundness of your investment only increases as you design and implement a renewable system that makes reasonable demands on this type of technology. Reasonable demand equates to reasonable loads. Renewable energy systems which utilize solar, wind, or hydro power are best suited for operating lighting, motors, pumps, electronic equipment, and the like. Heating loads, such as electric baseboards, water heaters, and ranges, along with older conventional refrigerators, place extremely high demands on R-E systems and are not cost effective. Avoid this by using the time-proven alternatives, such as propane for heating water and cooking or a wood stove for warmth. Conventional refrigeration manufactures have come a long way in making affordable energy efficient appliances available. We suggest making a trip to Sears or your local appliance store and compare the EPA Energy Guide of new refrigerators to your current one. While the Energy Guide is an average estimate, we have found them to be close to actual consumption. Another option would be to use a propane or natural gas refrigerator. Finally, at any step into this planning process, put our 34 years of combined expertise in renewable energy systems to work. Our customer service includes everything from troubleshooting to total system design. If you’re going to run your own power company, you’ll want to become knowledgeable enough to make daily operations and periodical maintenance a breeze, but for the times this is not enough, our customers appreciate the ready access to technical assistance long after our products are installed. Contact us using our tech support line, fax line, or on-line by e-mail. For all the questions along the way to making renewable energy a rewarding experience, put Northwest Energy Storage to work for you! Ask yourself these questions to determine if your site is capable of using renewable energy.
1. Calculate Your Power Consumption You need to estimate the demand for power, also known as the size of the load. Use accurate figures in your calculations and avoid guesswork. To aid in this critical step we suggest you purchase a Digital A/C power meter . This meter takes all the guess work out of determining your daily consumption and gives us hard data when selecting components. The meter is simply plugged into a wall outlet and the appliance to be tested is then plugged into the meter. Certain appliances like your refrigerator and computer will require the meter to be connected for several days to get an accurate accounting of energy consumed. When each appliance is tallied, we will have a clear view of your daily power consumption, as measured in watt hours. A close look at your tally will show you where your power is going and how you might effectively make reductions. Once you know the projected size of your daily load in watt hours, a system can be designed that meets these needs with cost-effective allowances for future expansion. 2. Determine the Best Power-Producing Resources of Your Site Of the three typical choices— hydro, wind, and solar power— the most common is solar, known as photovoltaic (PV). Hydro power costs less than PV but requires intensive maintenance when compared to solar. Few people live where the wind is adequate for generating power, but you can purchase a small wind plant for less money than you can buy good quality wind measuring equipment. Doing so will allow you to test your sites wind capabilities while generating usable power. 3. Size Your Power Generating System Because solar modules come in many sizes, shapes and applications, we suggest letting us help choose the array components. As your demand for energy grows, additional modules can be added anytime after the initial installation and different brands are usually interchangeable. In climates with low seasonal sunshine it is much easier on the budget to add a backup generator to supplement your solar array. Consider sizing your PV system to provide your annual average needs, with a generator for backup. We have designed software specifically for system sizing and are more than willing to help in this step.4. Consider the Voltage: 12, 24, or 48 Volts The size of your system will normally determine the choice of voltage. Small off grid systems often use 12 volts as most loads are DC. (Some loads may be A/C through an inverter). Availability of lights and small appliances at this voltage is fair, but are more expensive and often less reliable than the A/C versions. Small utility backup systems also use 12 volts through an inverter to keep costs lower. Medium to large systems benefit from 24 volts as line power loss is reduced and larger inverters can be used. This type of system lends itself to A/C loads and the use of conventional A/C wiring which is typical in most existing homes. Large systems can utilize a 48 volt system effectively, and like the 24 volt system, benefit from efficient A/C lighting and the use of readily available conventional A/C appliances.
The battery, the heart of any R-E system, converts chemical energy into electrical energy. (read a more detailed description about batteries in the “Battery” section of this catalog) Deciding on just the right battery is a critical decision because batteries, unlike other R-E system components, require a significant amount of monitoring and maintenance to ensure the longest life span. At Northwest Energy Storage, we provide you with detailed monitoring and maintenance instructions for the particular battery you select for your R-E system. Knowing and following these instructions will protect your investment for years to come. As you consider different battery configurations, note the total number of cells required. More battery cells means increased maintenance, whereas a similar capacity in a configuration that uses fewer cells decreases the time and effort required for routine tasks. Since the battery is the only component that needs consistent monitoring and maintenance, you need to balance the variables of the investment cost, the battery warranty, and your time available for routine tasks. However, don’t undersize your system: give due thought to possible increased demand in the future. Whereas PV modules can be easily increased, even years after the initial installation, batteries cannot. To avoid problems, batteries operating together should be the same age and amp/hour capacity. We offer several cost-effective choices: industrial quality deep-cycle (Hup Solar-One), high quality deep-cycle (Surrette), and good quality golf cart batteries. They are rated by the manufacturers on how many deep/shallow cycles each battery can deliver over its lifetime, warranties range from 1 to 10 years.
Generators provide backup power during periods when the RE source is inadequate, such as cloudy weather for a PV system or through extend power outages in a utility connected system. Also, generators provide power for those periods when the loads on a system are much larger than normal. The battery charger converts AC power from the generator to DC power which can be used to charge the batteries. All of the inverters we offer include a battery charger function. Avoid under-sizing either the generator or charger for the loads you anticipate running. They should be sized to allow a timely charging of your batteries while also powering any loads you may be simultaneously running. Under-sizing will cause the generator to run for excessively long periods with a loss of efficiency.
Two choices in types of power are available: sine-wave or modified sine-wave. The sine-wave inverters will provide exceptionally “clean” power for sensitive equipment, such as computer systems, copy equipment, microwaves, audio equipment, bread makers and some motors. For instance, microwaves can take 30% longer to cook, fan motors may hum, stereos may have static, and copiers fail to operate in a system using a modified sine-wave inverter. As with other components, weigh these considerations against the cost differences for the best choice in your system.
All appliances should be looked at closely. Another example is the TV. By looking on the back and reading the fine print, you’ll notice that the same sized units can vary 30% or more in power consumption, and the list goes on and on. Make efficiency a priority and you’ll realize significant savings on the cost of your RE system. Finally, remember that your entire house should be considered as a whole, and that everything from insulation to light bulbs ultimately contributes to the efficiency you’ll achieve and, as a consequence, the saving you’ll realize over a lifetime of use and enjoyment. Ultimately, a home that makes sense for an R-E system will make sense for the people who live in it. Many household appliances consume power even after you turn them off. Examples of these loads are: TVs, stereos, satellite receivers, microwave ovens, modern gas ranges, answering machines and the like. You have 4 options in dealing with this problem.
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