architecture tips

There are more than one reason to use an off-grid system and often a mixed system allowing you to use the grid as a backup is an appropriate implementation. When moving towards a more sustainable office or home environment you are likely to employ alternative energy generation techniques which may commonly reach from Solar or Wind to Propane Combustion Engines. Following is a brief outline of the main topologies:

Tri-Generation
There is the tri-generation environment where typically Grid-Power, Propane Generators and Solar and/or Wind are all feeding the same system. This is for mission critical applications where power will always be available at the lowest cost and as much renewable power as generated is used.

In a tri-generation environment AC is normally the distribution method, this may change in the future to DC at least for the lighting system, computer backup and air-conditioning.

On-Grid System
An On-Grid System is based on Solar or PV Generators feeding the grid via a separate meter and a DC to AC converter, the energy supplied to the grid is credited to your account. The energy used by you from the grid is charged as usual. There is no backup to the grid, if the grid fails there is no energy.

Grid Assist
A Grid Assist System is typically based on Solar and Wind Generation coupled with the grid charging the storage batteries when insufficient wind or sunlight is available.

Off-Grid System
An off grid system can be Solar and Wind Generation only or coupled with a Diesel, Gasoline or Propane Generator to allow seamless energy during spells of no wind or insufficient sunlight but no connection to the grid. The supplementary generator would use electronics to automatically start if batteries need charging and no solar or wind power is available.

Generation using Combustion Engines
In 2008 propane was officially declared a renewable energy receiving the same federal assistance as other renewable programs such as wind and solar. As propane is a by-product of dormant and active oil wells it was available in abundance and rather than burning it off at the well or the raffinery it can be put to good use for fuel in vehicles with combustion engines, heating or electrical energy generation using turbines, piston or Wankel combustion engines. However, the most cost effective form of energy is Natural Gas where it is available as Propane has now reached the same prices as any other form of gas or petroleum that can be put into a car.

Electricity Generation using Solar PV Panels
Photo Voltaic (PV) panels convert light into electricity and are best suited in regions with a fair amount of clear skies their efficiency ranges from 5..10% of light energy converted to electricity. The only maintenance required is to remove dust from the panels from time to time especially in dry weather conditions. The cleaning frequency ranges from 3 days in Texas and Arizona to a weak or two in less dusty areas.

PV Generation requires a storage medium, mainly batteries. Various voltages can be applied but the safest voltage is 48V while optimizing the conductor size. Lower voltages would require larger conductors and are therefore more expensive, higher voltages are more dangerous as High Voltage DC is more dangerous in case of a person touching the terminals.

Klaus Bollmann is a 30 year veteran in energy conservation, resource saving innovative products for a sustainable environment. Click the link If you are interested in Ringdale DC Systems high performance 48V DC products or ActiveLED 48V DC capable lighting systems.

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The number of misinformation and the excuses used by propagates of the consume society to obscure or redefine the meaning of Return Of Investment or ROI is mind-boggling and so is the way purchasing departments have been conditioned to no longer believe that any lighting equipment can last beyond 3 years.

There is only one scientific way for ROI which will be discussed in this article ROI of Sustainable Environments, which clearly shows the payback can be significantly better than any conventional planned obsolescence model.

Major lighting operations usually have a maintenance budget to pay for the people and materials required to uphold the light levels that the organization has set or can afford. In a hotel or hospitality environment the MR-16 type light bulbs of conventional build last about 9 months and usually a crew of three to five people constantly run around from room to room and hallway to hallway to replace bulbs. However, once the crew is on board the maintenance people only look at the cost of the bulbs themselves rather than the peoples' time to accommodate the process, which is a significantly higher cost.

Therefore, from a maintenance crew's perspective the budget will only allow the lights to be replaced within the hardware replacement budget which does not allow the replacement of the fixture.

Organizational management usually has set aside funds to replace some or all of the lighting fixtures every 3 to 5 years, to make sure the buildings do not become a fire hazard. It is generally assumed that the cost for the maintenance does not play into the fixture and fittings budget. It has become an accepted fact that fixtures do fail within that period and purchasers and planners have been conditioned for that to be the norm and not to be overcome.

With the application of today's technology the perceived inevitable need to replace fixtures and or ballasts every 3 to 5 years, and the bulbs a few times more, no longer holds true. There is technology that can and will outlast 10 years while maintaining light output. However that technology is also at a higher initial cost but at a much reduced running cost in terms of energy use and maintenance.

First Fundamental for Calculating ROI
The fundamentals of calculating ROI start with the assumption of how long the organization intends to hold or operate the asset that requires reliable lighting.

If the answer is one to three years, then the cheapest form of lighting may be the best way to optimize profits. Using the cheapest is clearly not the best way for the environment due to; excessive generation of waste, poisoning the environment with mercury and excessive energy use further requiring excessive air conditioning, if the lighting is for indoor spaces.

2nd Fundamental - The ROI time-span
You have to accept the realistic lifetimes of the lighting products proposed. Look at the warranties the manufacturers offer and that they are providing a believable warranty in your region of operation so that the warranty can be drawn upon should there be issues.

Presentations by the incumbent brands, that light loss of any technology is inevitable, are incorrect and deliberately mis-leading to allow conventional technology to have a justification to be used. However, if there is any justification not to use Energy Saving long life, no light loss technology, it is in the First Fundamental for Calculating ROI.

Determine if the Light Fixture or Air Conditioning units, as warranted by the manufacturer, outlast the structure or if the structure outlasts the life of the equipment. Whichever is the shorter is the ROI time-span to be used for the ROI calculation. All equipment, conventional obsolescence model and new technology permanent model, has to be measured against the longest ROI time-span.

New Construction for use of Owner
There is a significantly different approach for determining the type of fixtures used in new construction depending on whether the new construction is for an Owner Occupied, Long Term Managed or for flipping in a short period after completion. Therefore ROI is not an appropriate way in the determination of which type of fixtures to use but whether or not the builder or the owner has to care about ongoing maintenance and running costs. For Owner Occupied or Long Term Managed buildings, lower running costs for maintenance and energy will mostly justify the increase in upfront investment for longer life lighting fixtures and controls.

Klaus Bollmann is a 30 year veteran in energy conservation, resource saving innovative products for a sustainable environment. Click the link If you are interested in Ringdale DC Systems high performance 48V DC products or ActiveLED 48V DC capapable lighting systems.

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There are many types of electrical energy storage; from capacitors, fly-wheel to rechargeable batteries of various technologies. However, in a home, office or factory environment only a few are practical or affordable.

On the battery side, as the most practical form of storage, there are some challenges and trade-offs that have to be considered. For example the cost of batteries and their specific performance in terms of charging efficiency, discharging efficiency and self-depletion performance versus price.

Charging from Solar or Wind will be most economical for a deep depleted 12 Volt flooded lead acid battery (10.7 volts at no load) to about 87% of charge with an efficiency of ~91%. From 87% to 100% the charging efficiency drops to 55% unless it is charged very slowly which will not be possible for daily cycles. The initial cost for a Raw Watt hour (R-Wh) for flooded lead acid batteries is approximately $0.24.. $0.19. The size of the battery capacity also depends on the way you want to use the battery. There will be two numbers of importance, the cost per Usable Watt hour (U-Wh) and the expected life time in cycle days.

The U-Wh are significantly lower than the R-Wh advertised by the manufacturer and depend on a number of other factors like the general area of operation between 55% discharge and 13% discharge. When operating in this area the charging efficiency is maximized to about 91% but the cycle life of a lead acid battery is greatly reduced and charts from the battery manufacturer have to be used to determine the realistic cycle life. When used with solar generation or load-balancing, a cycle day is mostly a day of the year. If your energy use is lower at the weekends this can extend lead acid battery life as anti-sulfurization charging can be applied during that period.

Charging Efficiency 91% (at U-Wh 32% of R-Wh)

Battery Type / Expected Cycle-Life (days)
Supermarket Chain Store 12 Volt Car Battery / 300 (less than a year)
Marine Deep Cycle / 400 (little more than a year)
Flooded Sealed Lead Acid (250 Ah/12 Volt) / 900 (2..3 years)
Flooded Managed Lead Acid (1000 Ah/12 Volt) / 1400 (4..5 years)

When flooded lead acid batteries are used in the area of operation between 90% charged and 70% charged (10% discharged to 30% discharged) the cycle life is greatly improved but the charging efficiency is not that good unless the batteries are charged very slowly in which case the charging efficiency can be improved to about 83%. In this case the battery capacity is derived from the most efficient charging rate resulting in very large battery banks.

Charging Efficiency 55% (U-Wh 20% or R-Wh)

Battery Type / Expected Cycle-Life (days)
Supermarket Chain Store 12 Volt Car Battery / 350 (less than a year)
Marine Deep Cycle / 450 (more than a year..1.5 years)
Flooded Sealed Lead Acid (250 Ah/12 Volt) / 1000 (5..6 years)
Flooded Managed Lead Acid (1000 Ah/12 Volt) / 1600 (7..10 years)

Charging Efficiency 95% (U-Wh 70% of R-Wh)

When using LiFePO or also known as Lithium Iron Phosphate batteries, the charging and discharging efficiency is significantly higher at around 95% at a higher percentage of U-Wh versus 100% of R-Wh, but the cost can be 2 to 3 times the cost of flooded lead acid having 2x extended cycle life at 80% of original capacity. Total economics work out to be exactly the same cost over 10 years as the equivalent flooded lead acid battery system for approximately the same storage and discharge performance. However, the storage space and weight for the same capacity is heavily in favour of LiFePO with 1/3-rd of the volume and weight of lead acid batteries, and half the weight and volume of Ni-Fe batteries. Also, when you start looking at nonideal conditions (cold, hot, unpredictable charge and depth of discharge), the lead acid battery performance falls off dramatically and it is worth the current cost of a LiFePO battery system.

Charging Efficiency 90% (U-Wh 80% of R-Wh)

When space and weight are not so critical a Ni-Fe Battery is a solution, it requires a storage and operating environment of 0°..45° C (32°..117°F) and therefore has to operate in-doors or in a crudely climate controlled area or more sophisticated cooling built into the battery cell. However, charging and discharging efficiency is high with 90% and the cycle time is in the 3000-plus cycles giving it a life time of 10 years plus. Ni-Fe batteries have been known to last 20 years retaining full capacity.

What this means for load-balancing systems based on batteries is that the cost for the equipment to charge the batteries efficiently as well as the correct battery size to optimize charging efficiency and life time (time to replacement) have to be carefully taken into account to determine system sizes that can produce a payback from load-balancing.

Both systems, flooded lead acid and LiFePO, will benefit from each cell fully managed by an appropriate charger controller rather than using multi-cell batteries that do not allow individual cell management or replacement. Ni-Fe batteries are more forgiving to overcharge and under-charge but require water-refilling on a regular basis or an automatic system to accomplish their automatic maintenance.

How often you have to change your batteries or supplement with extra capacity will affect your ROI or cost per stored and released Watt hour (Wh). You may decide it is more cost-effective to add 20% new batteries at the end of the 80% cycle life if your type of battery will continue to lessen its capacity at the same rate per cycle as it did up to the 80% capacity point. In this case you have to plan the space required for the extra 20% beforehand. You can then decommission 20% when the total capacity has reached 80% again and replace with 20% of new batteries and so on.

Disclaimer
In this article no claim is made as to the accuracy of any values, prices or other information given as they are rough indications or estimations based on publicly available information and the author's experience.

Tips for Selecting a Battery
Some battery manufacturers are masters in misrepresenting the true performance of their products.

Although a Supermarket Chain Store battery normally has a 1 year warranty, it has no Amp hour (Ah) nor a Wh rating and would only survive 150 deep discharge to fully charged cycles depleting its capacity to 50% or failing completely.

Do not use batteries for which you can not obtain cycle life diagrams showing after how many deep cycles the 80% mark of capacity is reached.

Starting a car or tractor once a day is not a deep cycle, cranking power and cranking cycles have no relevance in a load balancing application.

A battery made for the application will have an Ah and or a Wh rating. Be aware that if your application is mission critical design the capacity taking the 80% of capacity at end of life into account.

Klaus Bollmann is a 30 year veteran in energy conservation, resource saving innovative products for a sustainable environment. Click the link If you are interested in Ringdale DC Systems high performance 48V DC products or ActiveLED 48V DC capapable lighting systems.

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An important part of reducing cost as well as saving resources will be the technique known as Load Balancing. Often municipalities get offered energy at night for free or even being paid to take a certain amount of energy at low usage times.

This is mainly due to the efficiencies of turbines at a certain production rate. This means that if you can take and store that energy at times of overproduction and use it at times of high demand instead of taking power from the grid, significant savings for energy providers and consumers can be achieved.

The only practical storage technology today are batteries, as conversion into hydrogen gas is currently too expensive a solutions while flywheels can only be used for very short-term storage. If you happen to have a lake of course you can pump water from a lower level to a higher level and drive turbines when you need the extra energy.

Battery technology is not perfect but better than it was 10 years ago and the best candidates are Lead Acid and LiFePO batteries as both are relatively maintenance free with LiFePO having the better charge/discharge efficiency. The cost is lower for Lead Acid technology but the weight and volumetric size is 4 times that of the LiFePO. The cycle-life of industrial Lead Acid batteries with 2000 to 3000 cycles is actually better than the 1500 to 2000 cycles of LiFePO batteries. However, the overall energy efficiency of LiFePO is much better.

Where does load balancing make sense? If you have already paid for your batteries to store energy from solar, wind or bio-mass generation adding load balancing makes great sense as you do not have to amortize all of your battery capacity from the savings of cheaper off-peak power.

There is another way of looking at load balancing that makes extreme sense, at least until energy providers increase their rates drastically, this is short-term load balancing or totally avoiding demand charges. In a way it actually helps energy providers by not having to have capacity on-line just in case you want to peak your energy use. This kind of load-balancing is also known as demand-muffling. Machines may have to be adapted or modified to be able to make use of this technique.

Demand Muffling stores energy in batteries of sufficient size to operate the machine for a full working day. The energy is fed into the system at a constant much lower rate thus balancing the demand over a 24 hour period or longer if the machine is only used sporadically. For ovens that take a lot of power to heat up initially but not so much to keep the temperature this can change the demand charge from the energy provider from several hundred dollars a month to none, allowing a very fast amortization of the investment into machine modification, battery chargers and batteries. Cycling electric ovens, Wave Solder and Re-flow Solder machines are ideal for this kind of conversion.

All the more reasons to believe that 48V-DC Systems or a mixed AC delivery combined with a local 48V-DC System to buffer energy as well as 48V-DC devices directly making use of DC power will enter home, office, factory and server farms over the coming years.

If you are and Architect, Interior Designer, Mechanical or Electrical Engineer get used to the fact that in a transitional period DC and AC systems have to be accommodated in sustainable environments and the planning for them is paramount to keep cost of transition affordable.

Klaus Bollmann is a 30 year veteran in energy conservation, resource saving innovative products for a sustainable environment. Click the link If you are interested in Ringdale DC Systems high performance 48V DC products or ActiveLED 48V DC capapable lighting systems.

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Solar cell technology has improved so much that energy generation can achieve efficiencies of around 10% and produce fully amortized power at $0.14 per kWh as much as many domestic users or a small companies would pay for grid supplied power today (2012). While wind power is more a supplementary generation that requires larger storage systems it can often be combined with solar. Bio mass is another feasible way of generating methane to drive combustion engines to generate electricity or burn it to create heat.

However, solar and wind depend on meteorological conditions to be suitable for the technology to work and efficiencies vary widely from region to region. Each climate region has its own challenges and requires its individual solution to create energy in a sustainable way.

Arctic and Subarctic Regions

We have not considered the arctic or sub-arctic regions as regions where more sustainable techniques can be applied. Those regions already use state-of-the-art techniques and mainly require heating in an environment where sun is scarce and wind may be blowing stronger than conventional turbines can sustain.

During times when sun and wind are usable the temperature differences and prolonged freezing as well as the abrasive effect of frozen water embedded in strong winds makes solar panels and wind turbines not a very viable option as they would have to be protected from the elements during adverse weather conditions or constantly maintained, those adverse conditions may exist for 2/3 rd's of the year.

Methane from biomass may be a small contributor where sufficient animal and human food and feces can be available for the digestive process of a biomass reactor. However, the buildings to house such a reactor might be quite expensive as the process works best between 68°F and 90°F and will therefore have to be a rather large thermos flask.

Equatorial Belt

This is the general region covering Latitude 27° South to 27° North. Basically, the area of the world where it would be the rarest of days when the temperature would drop below the freezing point. Although warm for most of the time, the tropical and wet regions have their challenges as neither wind nor long periods of sunshine exist for long periods of the year. In the rainy season, days are often overcast or having half a day of rain and half a day of hazy sunshine and that season lasts usually for several months.

Right on the Equator

This is the region 0° to +/- 5° latitude where there is hardly ever any wind and year- round it is between 25°C and 33°C so cooling and de-humidification are the only requirements. From a Solar Generation point of view this region has its challenges. Although not particularly wet, it is often hazy and in the wet season where half of the day's sunshine is often lost to rain. However, the lowest temperatures will never reach freezing point, and dust is not that big an issue especially as it rains from time to time helping to clean the solar panels. It is a possible region for solar generation but storage capacity has to be higher and solar PV acreage has to be higher to deal with the worst months in the seasons where average daily sunshine may be as low as 5 hours a day for a whole month. Wind speeds, unless a typhoon comes by, are generally low and do not yield a lot for wind generation.

Tropical Region

This region is for example around Panama and El Salvador between 10° and 15° North is very wet in the summer from July to end of October leaving an average of only 4.5 hours of usable sunlight. It requires the generation capability to be double the size of dry regions. Average low temperatures will never reach freezing point so no special, only rudimentary anti-freezing methods have to be employed.

Fully Sustainable Region

The most sustainable region for indoor climate control is between the latitude of 25° to 37° North and South of the Equator. This is due to the fact that those regions are Humid Continental, Semiarid, Arid or Humid Subtropical or in other words a reasonable mix of sunshine all year-round with reasonably clear skies and small amounts of cloudy days.

Assisted Sustainable Region

This is the latitudal region between 37° and 45° covering Humid Subtropical, Semiarid, Arid and Mediterranean climates or in other words a reasonable mix of sunshine all year-round with reasonably clear skies and small amounts of cloudy days. However, because temperatures may reach freezing or below and substantial supplemental heating is required from time to time we call it "assisted sustainable". The best method of assistance is Natural Gas as the most cost efficient for heating, followed by electricity followed by propane and solid fuels.

Biomass Generation

With new technology becoming available to reduce the constant need to monitor and react to adverse developments in the reactor, this technology should get more consideration from now on. As biomass is normally available, in the arctic and sub-arctic regions to some degree, and available in abundance where human, animal or agricultural concentrations occur, therefore a digester / methane reactor is very feasible. However, economy of scale has to be considered as those systems require substantial and constant monitoring to maintain their efficiency. Also the re-use of the digested material has to be organized, a logistics issue that does not exist with solar or wind.

Storage of Energy

The storage of the biomass generated energy would be in form of liquid methane in super cooled containers that allow long term storage with little appreciable loss. The sotrage of solar and wind energy would be in a battery of some sort. The price per generated and stored kWh above was based on Lead Acid storage systems of industrial quality with a minimum battery life of 14 years.

Conclusion

Most regions, other than the cold extreme, lend themselves to harvesting of wind, sun and biomass renewable energy at a reasonable amortized cost. The amortization times are between 14 and 20 years depending on the technology, region and application specific circumstances. The systems can be designed to be fully automated and user friendly and provide lighting, heating and cooling under all seasonal weather conditions, but may have to be assisted by grid supplied energy or other fossil energy at times depending on the region.

Klaus Bollmann is a 30 year veteran in energy conservation, resource saving innovative products for a sustainable environment. Click the link If you are interested in ActiveLED high performance lighting and energy saving control products.

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