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PV Panels, Led Lighting, Solar Domestic Heating, Solar Heating, Solar On Demand Water,

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Salar Off Grid Cabin


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Passive Solar Domestic Hot Water

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Designing Stand Alone PV System

Battery Sizing

Solar Panel Array Sizing

Off-Grid Solar-Electric Systems

Although they are most common in remote locations without utility grid service, off-grid solar-electric systems can work anywhere. These systems operate independently from the grid to provide all of a household’s electricity. That means no electric bills and no blackouts—at least none caused by grid failures. People choose to live off-grid for a variety of reasons, including the prohibitive cost of bringing utility lines to remote homesites, the appeal of an independent lifestyle, or the general reliability a solar-electric system provides. Those who choose to live off-grid often need to make adjustments to when and how they use electricity, so they can live within the limitations of the system’s design. This doesn’t necessarily imply doing without, but rather is a shift to a more conscientious use of electricity.

Off Grid Diagram

Off Grid Homes

Off Grid living

Stand Alone Solar Systems with Generator backup

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If you would like a free design contact us with a description of your project

Off Grid Heat

Heat your existing Cabin or Cottage Domestic Hot Water with Solar

Checkout $897 Sale Price

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Solar Water Heating

Solar water heating

Let us do a free design analysis for your cottage

To do a solar design and financial analysis of your home or building
Require the following
Your geographic location
How many persons living in your home
What you are currently using for heat source, natural gas, electricity ,
propane, oil, wood
Size of home or building
Number of floors
look forward to doing your free analysis

If you would like a free design contact us with a description of your project

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WSE has been involved with several off grid applications like the one below on a remote island in northern Saskatchewan.

Each application is a bit different but the concepts are much the same

WSE is also partnered with Vereco Net Zero Homes and would be happy to design and build your your next net zero off grid cottage or cabin

Below is some examples of a cabin on a remote island in Northern Saskatchewan

This particular design was for summer usage only

solar cabin solar cabin

solar cabinOff Grid cabin

On Demand Water

The cabin is about 150 feet from shore and about 50 feet above the water.

The first pump is placed as close to the water as possible. A 12 volt deep cycle battery is positioned near the pump. The battery to connected to the main battery source with 12 gauge wire. An on/off switch is required to turn off when not requiring water.

The battery is connected is connected to the solar panels using 12 gauge wire to trickle charge the battery. In some cases a small 20 watt PV panel could be used to charge the batter instead of stringing the 12 volt wire.

on demand water pump

The second pump is at the cabin supplying the cold water supply and the WSE47-20 solar hot water heater. The pump is connected to the main battery supply thru an on/off switch.

solar on demand water

The WSE47-20 incorporates a float valve which turns off the water supply when the 140 liter tank is full.

The WSE47 -20 supplies the hot water for your hot water needs

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Solar Water Heating Off Grid

Low Cost Solar Domestic Water Heating for your Cabin

This system is a dream come true for cabin owners that want a low cost solar domestic water heating

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The third pump supplies the hot water to the cabin.

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Installed 2 - 100 watt solar panels and connected thru 30 amp solar controller.

200 watt PV panels

Thin Film PV

25 Watt 12 volt Thin Film Panels

WSE can do free analysis to determine your PV and battery requirements

Please check the WSE Polysun analysis of a cabin in La Ronge Saskatchewan using 2,000 watts a day

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30 am solar controller

Solar Controller

Ensures battery doesn't overcharge from Solar panels

Includes battery gauge

PV voltage

Battery voltage

Charge current and wattage

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Solar Battery

Favorite Battery

6 volt 220AH

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Xantrex Inverter

The Freedom HF Inverter/Chargers are the smallest, lightest, and least expensive

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Solar NetFlix

Living on Remote Island in Saskatchewan with all the Solar Toys

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Led Lighting

The WSE Aluminum Strip Light is a great product that works in many different applications.

The Aluminum Strip Light is a 12VDC unit and is available in both warm white and cool white, as well as 50cm and 100cm lengths.

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Off-Grid System Sizing
The size of an off-grid solar electric system depends on the amount of power that is required (watts), the amount of time it is used (hours) and the amount of energy available from the sun

Be Energy Conservative
Being concersative plays an important role in keeping down the cost of a photovoltaic system. The use of energy-efficient appliances and lighting, as well as non-electric alternatives wherever possible, can make solar electricity a cost-competitive alternative to gasoline generators and, in some cases, utility power.

Cooking, Heating and Cooling
Conventional electric cooking, space heating and water heating equipment use a prohibitive amount of electricity. Electric ranges use 1500 watts or more per burner, so bottled propane or natural gas is a popular alternative to electricity for cooking. A microwave oven has about the same power draw, but since food cooks more quickly, the amount of kilowatt hours used may not be large. Propane, wood or solar-heated water are generally better alternatives for space heating. Good passive solar design and proper insulation can reduce the need for winter heating. Evaporative cooling is a more reasonable load than air conditioning and in locations with low humidity, the results are almost as good. One big plus for solar cooling: the largest amount of solar energy is available when the need for cooling is the greatest.

Lighting requires the most study since many options exist in type, size, voltage and placement. The type of lighting that is best for one system may not be right for another. The first decision iswhether your lights will be run on low voltage direct current (DC) or conventional 120-volt alternating current (AC). In a small home, an RV, or a boat, low voltage DC lighting is often the best choice.
DC wiring runs can be kept short, allowing the use of fairly small gauge wire. Since an inverter is not required, the system cost is lower. When an inverter is part of the system, and the lights are powered directly by the battery, a home will not be dark if the inverter fails. In addition to conventional-size medium-base low voltage bulbs, the user can choose from a large selection of DC fluorescent lights, which have 3 to 4 times the light output per watt
of power used compared with incandescent types. High quality fluorescent lights are available for 12- and 24-volt systems. LED lighting is improving rapidly and already meets or beats the light output and efficiency of fluourescent lighting.

Gas powered absorption refrigerators are a good choice in small systems if bottled gas is available. Modern absorption refrigerators consume 5-10 gallons of LP gas/month. If an electric refrigerator will be used in a standalone system, it should be a high-efficiency type. Some high-efficiency conventional AC refrigerators use as
little as 1200 watt-hours of electricity/day at a 70º average air temperature.
Major Appliances
Standard AC electric motors in washing machines, larger shop machinery and tools, swamp coolers, pumps, etc. (usually 1/4 to 3/4 horsepower) require a large inverter. Often, a 2000 watt or larger inverter will be required. These electric motors are sometimes hard to start on inverter power, they consume relatively large amounts of electricity, and they are very wasteful compared to high-efficiency motors, which use 50% to 75% less electricity. A
standard washing machine uses between 300 and 500 watt-hours per load, but new front-loading models use less than 1/2 as much power. If the appliance is used more than a few hours per week, it is often cheaper to pay more for a high-efficiency appliance rather than make your electrical system larger to support a low efficiency load. Vacuum cleaners usually consume 600 to 1,000 watts, depending on how powerful they are, about twice what a
washer uses, but most vacuum cleaners will operate on inverters larger than 1,000 watts since they have low-surge motors.
Small Appliances
Many small appliances such as irons, toasters and hair dryers consume a very large amount of power when they are used but by their nature require very short or infrequent use periods. If the system inverter and batteries are large enough, they will be usable. Electronic equipment, such as stereos, televisions, VCRs and computers have a fairly small power draw. Many of these are available in low voltage DC as well as conventional AC versions.
In general, DC models use less power than their AC counterparts

Designing Stand Alone PV System

Living off the grid is a romantic ambition for some, a practical necessity for others. But whatever your motivation for off-grid living, cutting the electrical umbilical cord from the utility shouldn't be taken lightly.
Before you pull out the calculator, size up the realities and challenges of living off the grid. Then, once you're stand-alone system.
Design Considerations
Designing a stand-alone PV system differs substantially from designing a batteryless grid-direct system. Instead of meeting the home's annual demand, a stand-alone system must be able to meet energy requirements every day of the year. The PV system must be able to keep the battery bank charged-or include a generator for backup-because once the last amp-hour is drawn, the lights go out (see "Backup Generators" sidebar).
Efficiency first! This long-standing mantra for PV system design still holds true and is especially important for offgrid
systems. Every $1 spent using energy efficiently is estimated to save between $3 and $5 on PV system costs. As a system designer, it's virtually impossible to mandate wise energy use by the end user, but we can specify efficient appliances, such as Energy Star refrigerators and clothes washers, and strategies, such as shifting loads to non-electric sources during times of low solar insolation. For more on efficiency and load-shifting.
Energy Consumption and the Solar Resource. Carefully comparing the home's daily and seasonal energy usage
with the daily and seasonal availability of the sun will help prevent energy production shortages. This important
step involves a careful analysis of the home's changing seasonal load profile and the corresponding solar resource
throughout the year. Paramount to this analysis is the presence or absence of a backup charging source, such as a
generator. If a backup charging source is not incorporated, the designer should choose as the design target the time of year when energy consumption is expected to be highest and the solar resource at its lowest-usually during the
depths of winter.
Without a backup generator, a PV system must produce every watt-hour required, at all times of the year. This is
often a tall task during the winter months and typically results in a costly system that is oversized for the rest of the
year. For this reason, stand-alone systems without a backup charging source are often limited to smaller, nonresidence applications, such as seasonal cabins.
For systems with a backup charging source, more design flexibility means designers can use average consumption
numbers and peak sun-hour values. For example, they can choose to size the system at a time of year when
energy consumption is not at its highest or lowest, but in the middle-say, a typical day in the fall or spring. In
addition, they might use the specific location's average solar resource. Using the average for both consumption and
sun-hours will strike a good balance between an affordable array size and generator run time. If minimal generator run time is desired, the array and battery bank may need to be upsized based on more conservative consumption and sun-hour values. a prerequisite to energy design and production.

Size it Up: A Case Study
Who: The Ackerman-Leist family
Where: Pawlet, Vermont, approximately 3/4 mile from
utility service
Solar window: 8 a.m. to 4 p.m.
Average daily solar resource: 4.6 peak sun-hours*
System backup: 4 kW backup engine generator
System voltage: 24 VDC
Projected energy use (AC and DC): 2.2 kWh per day
Expected avg. ambient temperature for batteries: 60°F
Record low temperature: -35°F
Desired days of autonomy: 3
Desired battery depth of discharge: 50%
Battery: 6 V nominal, 225 Ah, deep-cycle flooded lead-acid
PV modules: 12 V nominal, 80 W STC , array tilt equal to the
latitude (43°)
Charge controller: MPPT, 60 A
Array mounting: Pole-mount
*Peak sun-hours are based on Concord, New Hampshire,
values, which more accurately reflect the site's latitude and
weather patterns.

Step 1: Estimate Electric Load
Determine the amount of energy (kWh or Wh) that will be consumed on a daily basis. If it is for a home not yet built, thiscan be a very involved and time-consuming step. A designer will need to work closely with the homeowner/builder to realistically estimate the daily and seasonal energy requirements.
The power (W) of individual loads and their estimated energy consumption (Wh) can be tallied to calculate the
household's average daily load. This step will help identify opportunities for efficiency improvements and pave the wayfor sizing the system components. The table below lists the electrical loads found in the Ackerman-Leist household. The family heats their home with wood, cooks with wood and propane, uses a propane refrigerator, and heats their water with a solar thermal system and a backup propane boiler, so
those are not factors in the load analysis.
According to the table, daily household loads average 1.8 AC kWh and 0.36 DC kWh (from the chest freezer), totaling almost 2.2 kWh a day.

Battery Bank Sizing
The average daily load is then used to calculate the battery requirements. The batteries must be able to store the total daily load, in addition to the extra energy lost by inverting from direct current (DC) to alternating current (AC). Dividing the AC average daily load by the inverter efficiency (90% standard), inflates the average daily load that the batteries must store to account for efficiency losses from the inverter.
While inverter manufacturers will commonly list "peak efficiency" (generally ranging from about 92% to 95%), we
use a more conservative 90% to account for the fact that the actual operating efficiency depends on the AC load, which is constantly fluctuating. Hence, an inverter will rarely operate at the load level which results in peak efficiency.
The battery bank's ambient operating temperature is also taken into consideration, since temperature affects a flooded lead-acid battery's internal resistance and ability to hold acharge. As temperatures fall below 80°F, battery capacity is reduced. A battery temperature multiplier table can be used-check with the battery manufacturer for their specific correction factors.
Days of autonomy is also an important design criterion, as it dictates how many days the battery bank will need
to sustain the average daily load when there is little or no sunshine to recharge it. It's a compromise between having
energy during overcast spells, how much time the generator will run, and the added cost of a larger battery bank. The more days of autonomy desired, the larger the battery bank.
Generally three to five days of autonomy provides a good balance. Keep in mind that the larger the battery bank, the larger the PV array will need to be to recharge the bank sufficiently on a regular basis-or the more the generator will be needed to pick up the slack.
The last major design criterion for sizing batteries is the depth of discharge (DOD). While deep-cycle lead-acid
batteries are designed to discharge 80% of their capacity, the deeper they are discharged on a regular basis, the
fewer charge/discharge cycles they can provide over their lifetime. When choosing a DOD, strike a balance between longevity, cost, and the significant hassle of replacement.
Many system designers will specify a 50% DOD to be used in the worksheet. Because several days of autonomy areaccounted for, which increases the battery bank size, the actual depth of discharge during sunny weather will often be less than 20%. The DOD design value can greatly affect the cost of the battery bank. (For simplicity, the numbers from the load table have been rounded in the following equations.)
(1,800 AC Wh Avg. Daily Load ÷ 0.9 Inv. Eff.) + 360 DC Wh Avg. Daily Load = 2,360 Wh/day
2,360 Wh/day ÷ 24 DC System Volts = 98.3 654.7 ÷ 225 Ah individual battery capacity = 3 parallel
battery strings (rounded up from 2.9)
24 V system voltage ÷ 6 V battery voltage = 4 batteries in
3 parallel strings x 4 batteries in series = 12 total batteries
The battery calculations indicate that a battery bank made up of 12 of the chosen 6 V, 225 Ah, flooded leadacid
batteries will provide adequate storage to meet daily energy requirements, inverter efficiency losses, operating
temperature effects, days of autonomy, and the desired average depth of discharge. The number of batteries or series strings of batteries connected in parallel should be kept to a minimum, preferably three or less. This minimizes the chance of unequal charging from one battery or string to the next.
While using higher-capacity batteries would have resulted in fewer parallel strings, the Ackerman-Leists chose lowe rcapacity batteries for budgetary reasons.Avg. Ah per day 98.3 x 1.11 battery temperature multiplier x 3 days
autonomy ÷ 0.5 DOD = 654.7 total system Ah

Batteries are rated by their capacity in amp-hours and at the rate that they are charged/discharged. In most PV systems, the appropriate Ah rating to use is based on a discharge over 20 hours. Unlike shallow-cycle vehicle batteries, deep-cycle batteries in PV systems are charged and discharged over 24 hours, and the weather, level of solar irradiance, and energy usage patterns all influence the charge/discharge scheme.
In this system example, the battery could provide 225 Ah of stored energy-if discharged 100% over 20 hours. If it were discharged faster, the capacity would be less, and vice versa. Be sure to check with the battery manufacturer, as they provide battery-specific Ah capacity values based on different charge/discharge rates. Choose the 20-hour rate when sizing and selecting batteries, unless a specific load profile dictates otherwise.

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Solar Panel Array Sizing
Now that we have calculated loads and storage, next calculate the array size in watts, and the number of PV modules needed. The array calculations must include Wh per day (calculated from the average daily load), the location's solar resource, expressed in daily peak sun-hours, battery efficiency losses
(about 20%), module temperature losses (about 12%), possible array shading, and a conservative derate multiplier to account for things like wire losses, module soiling, and production tolerance.
Peak sun-hours are the equivalent number of hours per day when solar irradiance (intensity) averages 1,000 watts per square meter, as derived from the National Solar Radiation Database

Dividing the Wh required by the location's peak sun-hours leaves us with the initial PV array watts needed. For this sizing example, the solar data for Concord, New Hampshire (at 43.2°N) provides the closest estimate of the solar resource for Pawlet, Vermont (at 43.3°N) at an array tilt angle equal to latitude. Since this system is using a backup generator, the average daily peak sun-hours can be used (4.6), as the generator can cover energy shortages during periods of low insolation or high energy consumption-or both. If less generator run time is desired, the array size must be increased or daily energy consumption must be reduced appropriately (or both).
Battery efficiency: Since batteries are not 100% efficient in converting electrical energy into chemical energy and back again, the array size must be increased to account for energy lost in the storage process. A common battery efficiency is 80%.
PV temperature losses: Module standard test conditions (STC) ratings, which are based upon a cell temperature of 77°F (25°C), don't reflect real-world operating conditions. To account for losses due to higher cell temperatures, a derating value of 0.88 can be used. This assumes an average daytime ambient temperature of 68ºF and an estimated cell temperature of 122°F. (Another way to calculate temperature losses would be to use the specific module's maximum power temperature coefficient, in conjunction with a cell temperature based on the record high daytime local temperature.)
Shading coefficient: Although 9 a.m. to 3 p.m. is often considered the ideal solar window, site-specific shading
should always be evaluated for the whole day. Even moderate shading can have a substantial impact on array output. In the case of this sizing example, with a shade-free solar window of 8 a.m. to 4 p.m., an average shading coefficient of 0.90 was determined with a Solar Pathfinder array siting tool.
Derate factor: A 0.85 derate factor (from NREL's PVWatts online performance calculator) accounts for other system losses, including module production tolerances, module mismatch, wiring losses, dust/soiling losses, etc. An
experienced designer can adjust this value to reflect conditionsfor your specific site. See the table for a summary of these values.

PV Solar Derate
2,360 Wh daily load ÷ 4.6 peak sun hours ÷ 0.8 battery efficiency ÷ 0.88 temp. losses ÷ 0.9 shading coefficient ÷
0.85 system derate = 953 W peak array
953 ÷ 80 W STC individual module = 12 modules needed 48 V nominal array voltage ÷ 12 V nominal module voltage = 4 modules per string, 3 strings total
The resulting 12-module array will have a capacity of 960W STC, rounded up slightly from the 953 W specified in the calculations. Although the DC system voltage and the battery bank are 24 VDC, this array can be wired at a higher voltage of 48 VDC, because of the "step-down" feature of the charge controller being used. Since the modules are nominally rated at 12 V, they will have to be wired into three series-strings of four modules each.
If these calculations seem conservative, it is because they are. It is imperative to design a system that will operate reliably and efficiently-and that will produce, on average, the expected amount of energy required. In other words, it is the designer's job to give the system manager/homeowner a realistic idea of what to expect

Solar Panel System

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See Throught Window Insulators - Save 40% on Energy Costs


Solar Water Heating

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Your Environmentally Friendly Hard Water Solution


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Green air conditioning ( 90 % energy use reduction)

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