Fontenot Contracting can assist you in evaluating the below areas to make your home more energy efficient:
The American Society of Heating, Refrigeration and Air Conditioning Engineers defines cogeneration, also referred to as combined heat and power, to be the simultaneous creation of electrical power and useful thermal energy from one energy stream such as oil, coal or natural gas. In some instances, the energy source can be supplied by a solar, geothermal, biomass or other type of renewable energy source. Cogeneration systems are becoming more prevalent in the residential sector because they can create both electricity and thermal energy from a single source of fuel, thereby increasing efficiency and decreasing emissions. Once reserved for large commercial applications and power plants, CHP systems work by capturing the excess heat produced by the combustion process. This heat can be used to heat space or hot water, often times able to satisfy the heating needs of the whole home.
These systems are attractive because they allow homeowners to produce their own heat and electricity at home from a single fuel source and with a single appliance. Also, because these systems can be set-up as heat-driven (meaning the supply heat first, with electricity as a by-product) or electricity-driven (the opposite) the can be adjusted to meet a home's specific needs. Furthermore, since these systems can be connected to the utility grid, they can be supplemented with energy when they fall short of the home's electricity demand or sell back to the grid when they exceed demand.
Despite the fact that they often rely on fossil fuels to provide their power, CHP systems are among the greenest possible appliances because they provide electricity at a fraction of the environmental cost of utility power due to their superior efficiency. Though there are still barriers to entry, such as the high initial cost and the lack of long-standing reliability data, CHP systems are a great option for almost all homeowners in our market who are capable to investing in a new HVAC system.†
The basic CHP system works by linking two main components - a generator and a furnace/boiler. Though the system can be configured to run both ways, most CHP systems are initiated by electricity generation. When heat is required for the home, the generator burns fuel to create electricity, producing significant excess heat in the process. This heat is captured by the secondary element and used to heat air or water that is distributed to the home via its pipe or duct system. When the heating demand exceeds this initial capacity, the boiler is fired to provide the additional heat. However, since the generator is already supplying most of the energy necessary to heat the home, the already super-efficient boiler uses a fraction of the fuel it might otherwise need to achieve the same temperature difference. All with the added benefit of electricity generation sufficient to power most of the home's electronic appliances.
These systems are the main mover of choice for smaller cogeneration applications because of their established technology, robust nature and reliability. Reciprocating internal combustion engines provide electricity and thermal energy through heat recovery from exhaust gas, engine oil and cooling water. A drawback to these systems is that they require regular maintenance servicing to guarantee availability. They are suitable for residential, commercial, institutional and small scale industrial loads because they come in a variety of sizes ranging form a few kilowatts to more than ten megawatts and can be run on a broad variety of readily available fuels.
For example, the 60-75 kW natural gas fuelled units of Tecogen Inc. can be used for residential cogeneration application. (More info under Company Profiles)
Though they are still deemed an emerging technology, these systems already have proven performance and environmentally beneficial advantages. This technology of directly converting chemical energy of a fuel to electrical energy by a hydrogen-oxygen fuel cell has recently experienced tremendous research. Fuel cell cogeneration systems have been argued to have the greatest potential in residential and smaller commercial applications because of their capacity to produce electricity at a higher efficiency compared to power plants and significantly reduce greenhouse emissions. NASA has utilized these systems for the past thirty years, and due to recent technological advancement fuel cells are more affordable for smaller scale application. Fuel cell cogeneration has many advantages, including low noise level, low maintenance, superior part load management, low emissions, and the capacity to achieve an efficiency level of 85-90% even with small systems. Furthermore, fuel cell systems do not utilize the combustion processes which reciprocating combustion engines use. This technology produces environmental benefits, which include decreasing carbon dioxide emissions by up to 49%, nitrogen oxide emissions by 91%, carbon monoxide emissions by 68%, and volatile organic compounds by 93%. The main drawback to these systems is that they have a high cost and potentially short lifetime. Companies (see for more info below): Acumentrics (Westwood, MA), CellTech Power (Westborough, MA), Plug Power (NY)
These systems have received increasing interest for use in residential and commercial cogeneration application because of their potential for high efficiency, good performance at partial load, fuel flexibility, low emissions levels and low vibration and noise levels. Because the technology is not yet fully developed, these systemsí use is not widespread. Unlike reciprocating internal combustion systems, the heat energy is supplied from external sources through a heater or heat exchanger, which allows for the use of a variety of energy sources such as fossil fuels or renewable energy sources like solar or biomass. Because the combustion process occurs externally of the engine, it is a well-controlled continuous process and the resulting products do not enter the engine. Since Stirling engines have a continuous combustion process, two power pulses per revolution and fewer moving parts in comparison to reciprocating internal combustion engines, these systems have low maintenance requirements and are quieter and smoother than reciprocating internal combustion systems. Companies (See below for more info): Sterling Technology Company (OHIO) and Sterling Thermal Motors, teamed up with DTE Energy
Technologically speaking, fuel cell and Stirling engine cogeneration systems are promising for residential use but their reliability and affordability must be improved for them to become widespread. Reciprocating internal combustion engines are more reasonably priced. And while reciprocating internal combustion systems have a higher electrical efficiency in comparison to Stirling engines, fuel cells offer the highest electrical efficiency in the residential environment.
Payback on investment varies with fuel cost, electricity cost, the availability of net metering (where the utility credits the customer for excess electricity placed onto the utility grid at the retail rate), and the need for the waste heat (e.g., a system heating a pool will provide useful heat and electricity in the summer and winter). Some units operate only when there is a need for heat and are therefore more cost-effective in cold climates. The best economics will be found in cold climates having high electric rates and low natural gas rates.
The extent of maintenance depends on the type of engine and the type of fuel. For a natural gas internal combustion engine, routine maintenance is required every 4,000 to 10,000 hours (about 1 to 3 years). At this interval, an oil and filter change, spark plug replacement, and minor adjustments are necessary. The servicing takes about one hour and costs about $200. It is imperative that internal combustion CHP systems have routine scheduled maintenance. Therefore, most manufacturers are offering systems through authorized installers who will also offer service contracts.
The large downside of these systems is their high initial cost, often†more than 50% higher than high-efficiency gas-fired boilers. The average estimated cost for a system ranges from $8,000 to $15,000. But because they reduce the electricity demand in most homes by almost 50% over the course of a year, the return on investment can often be realized inside of ten years. Additionally, most manufacturers boast anywhere from a $5,000 to $20,000 jump in home value as a result of installation.†
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"High-Efficiency" boilers and furnaces can be powered by any fuel. In our market, natural gas is the most prevalent fuel source. These systems operate by the same mechanism as their traditional counterparts, using the heat from combustion of the fuel to increase the temperature in the home by means of a transmission fluid - either air or water. Commonly referred to as "forced hot air" (furnaces and boilers, by way of hydrocoil) and "forced hot water" (boilers), these systems rely on a pumping system or fan to circulate the heated medium to other parts of the home and return it to the boiler or furnace after the heat exchange has taken place.
There are literally thousands of models of boilers and furnaces that claim the label "high-efficiency." Efficiency calculations can be made in many different ways, however, and are often confusing and misleading to homeowners who don't have backgrounds in the field. The most important efficiency calculations are always the ones made from personal experience - that is, the amount of fuel used and the amount of heat produced in each individual application over time. However, because this information is only available after installation, there are a number of measurements that can be used to estimate the efficiency of a boiler or furnace before it is installed in order to make the most informed decision about a new appliance.
Many of these "high-efficiency" appliances make claims of up to 98% efficiency. However, these numbers most often refer to steady-state thermal efficiency, which is a measure of how much of the energy stored in the fuel is actually turned into heat energy when the unit is operating at peak output. The regularity with which an HVAC unit operates at that load, combined with the efficiency of the transfer systems, can significantly mitigate these efficiency stats. A better measure of applied efficiency is AFUE, or Annual Fuel Utilization Efficiency. While it is important to recognize that the furnace or boiler is only one part of a complicated system, improving its efficiency is a very important step to making the system as a whole more efficient
A home's HVAC system is almost always its largest consumer of electricity. Because heating and cooling air is an energy-intensive process, there are many factors that go into the selection of an appropriate HVAC system. Properly sizing, along with the installation of efficient systems, can go a long way toward improving a home's environmental footprint and saving money on energy costs.†
High efficiency models are often significantly more expensive than their traditional counterparts, but because many homes in our market are using outdated equipment to meet their needs, these initial costs can often be recouped relatively quickly. For example, a homeowner with a boiler operating at 60% AFUE who paid $2500 in heating costs last year could save almost $1,000 dollars by switching to a boiler with 95% AFUE, assuming the costs of fuel stays constant. (60% / 95% x $2500 = $1,578).†The estimated average cost for a high-efficiency boiler ranges from $5,000 to $10,000.
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Geothermal technologies are also referred to as ground source heat pumps (GSHP). These are electrically powered systems that utilize the stored energy of the earth. They use the earthís reasonably consistent temperature, approximately 55 degrees, to provide heating, cooling, and hot water for residential and commercial purposes. Geothermal systems have been endorsed by the United States Department of Energy (DOE) and the Environmental Protection Agency (EPA) as one of the most energy efficient and environmentally-friendly heating, cooling and water heating systems. The DOE estimates that geothermal systems use between 25-50% less energy on average than conventional systems, providing up between 44-77% in energy savings.
Geothermal systems can be installed on practically any lot size: under lawns, landscaping, driveways or the house. Additionally, an existing house can be retrofitted with a geothermal system by using the ductwork in place. In many cases, particularly in climate regions like New Englandís, geothermal heat pumps need to be supplemented by other heating systems to satisfy winter heating demands.
An EPA report found that geothermal systems provide an opportunity to reduce national energy use and pollution, and deliver comfort, reliability and savings to homeowners.
A GSHP can be a combination heating/cooling and hot water heating system. You can change from one mode to another with a simple flick on your indoor thermostat. Using a desuperheater, some GSHPs can save you up to 50% on your water-heating bill by preheating tank water.
A water-filled, closed loop of high-density polyethylene (HDPE) pipe transports heat between the earth and the residence. These pipes bring lukewarm water in through basement walls. Thermal conductivity is maximized through backfilling holes with bentonite grout.
Once in the house, the water is cycled through the pipe loop to the geothermal unit, which functions as a furnace and air conditioner. This system utilizes refrigerant and the water from the underground pipes to heat or cool the air. The air is then circulated through ductwork that is the same as that found in a conventional forced-air system. However, the temperature of the air that comes out of the registers is different. With a standard air source heat pump, the air flow rarely surpasses 80 degrees. Since water transfers a greater volume of heat than air, the earth source heat pump is capable of delivering warmer air, close to 110 degrees F.
An optional feature to a geothermal system is a desuperheater, a device that utilizes excess heat to warm up domestic water at no additional cost.
"Air in the ducts (1), refrigerant in the geothermal unit (2), and water in pipes (3) flow past each other like interlocking gears. Water brought from underground transfers heat to the refrigerant, or absorbs heat from it, depending on the season. Like an air conditioner, the unit compresses or expands the refrigerant to raise or lower its temperature. Finally, the refrigerant, now heated to 180 F or chilled to 40 F, fills condenser/evaporator coils. Air in the ducts blows across the coils to be cooled or warmed, then flows through the house." (source)
There are two types of geothermal heat pumps; open and closed, with three basic configurations for each.
-Open systems directly exchange water with a nearby aquifer, and tend to be more efficient. However, these types are not applicable in our market.
-Closed systems are far more abundant and use indirect heat exchange. There are three main types of closed system: horizontal, vertical, and pond.
Horizontal systems (2 in the above picture), rely on pipes inserted in trenches between 3 to 6 feet deep, with a typical buried depth of about 4 feet. If enough space is available, this is typically the least expensive and invasive type of installation. Because horizontal systems use less pumping energy, they typically draw less electricity. However, they are typically less efficient than vertical installations.
Vertical systems (1 in the above picture), are built by drilling pipes that go 100-150 feet into the earth. The more costly installation of this system relative to that of horizontal systems may be offset by efficiency gains.
A pond or lake installation (3 in the above picture) is applicable when the property is adjacent to a body of water. This system is features pipes that are laid in coils on the body of waterís bottom. When feasible, this application is least costly to install.
Geothermal services are one of the most efficient residential heating and cooling systems available, with heating efficiencies 50 to 70 percent higher than standard heating systems, and cooling efficiencies 20 to 40 percent higher than available air conditioners. Such efficiency translates into lower utility bills.
Geothermal services can result in 44% to 77% in energy savings. Also, significant financial incentives exist for homeowners who choose to include geothermal as part of their energy production systems. Under the American Recovery and Reinvestment Act of 2009, homeowners may receive a tax credit of 30% of the total installation costs, with no maximum credit amount. Other state and local incentives may apply. There is a vary wide range of installed cost that are very site specific. The initial capital expenditure is significantly more than co-generation or high efficiency boilers. In terms of ROI, geothermal is most suited for someone who plans to be in their home for longer time frames.
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Solar technology continues to evolve quickly as demand increases and energy prices continue to climb. In Massachusetts, multiple manufacturers and installers are currently operating, and for the most part have been assisted by state, local, and federal agencies. Solar power refers to electricity that is produced from the sun. The sunís radiated energy can be converted directly to electricity in photovoltaic (PV) cells. Multiple cells are joined in series and mounted together on a support structure called a photovoltaic panel. These panels have the same qualities of the cells, only increased in scale based on the number of cells in the connection. Small panels typically have 32-40 series-connected cells, which can produce voltages of up to 20 volts at an open circuit, and 16-17 volts at peak load (demand). These voltage levels can charge 12 volt batteries through a charge regulator. Larger commercial panels are available for residences which have up to 100 voltages. Adding more panels will further increase the output voltage.
Solar cells in the panels installed on your roof convert sunlight directly into DC power (direct current). The DC is incompatible with the AC (alternating current) that is supplied by electric utilities and used by residential electrical devices. DC power must be converted to AC power through a component called the inverter. This system is interconnected with your electrical utility. If more electricity is produced by the solar power system than your home is using during the day, the utility will allow net metering for the excess power generated being returned to the grid. Your utility would provide power as usual at night and during the day when your electricity demand exceeds that produced by your solar system. Systems are also available with a battery backup.
A grid-tied PV system collects energy from the solar cells, uses an inverter to convert the DC electricity to standard, household AC electricity that can be used by appliances and accessed through standard outlets. When the solar cells are producing more energy than is being used by the household, the excess energy is fed into the larger grid - literally running the homeowner's utility meter backwards. When the home's power demand exceeds the production of the solar cells, energy is seamlessly drawn from the grid to make up the difference. This concept is called net-metering.†
Grid-tied PV systems have a number of significant advantages. First, net-metering provides a easy way to make sure that excess power generation is not wasted or lost while also encouraging homeowners to engage in energy-efficient behaviors so as to draw as little power from the grid as is necessary. Second, it eliminates the need for costly, cumbersome, and toxic physical storage solutions like batteries.
The main disadvantage of a grid-tied PV system is that it provides no protection against power loss. Because the current flows through the same mechanism that delivers power from the grid, this type of system will be of no use when utility service is lost due to weather or other conditions. Despite this shortcoming, a grid-tied PV system is the best option for most homeowners in our market.
Like grid-tied systems, battery systems harvest energy from the solar cells and use an inverter to create usable current. However, instead of feeding excess energy into the grid, these systems use batteries to store that energy for future use. There are several key advantages and disadvantages to this type of PV system.
A system with battery backup has the unique advantage of being able to provide energy regardless of utility conditions, making its owners relatively independent of the utility service. For this reason, battery backup systems are often found in rural conditions where the grid is inaccessible or unreliable. For some, this autonomy from the grid is an emotional or ideological value add.†
Aside from the real or perceived value of independence, battery backup systems have few advantages. Storing energy in battery form and then recovering it later is an inherently inefficient process, as it both conversions are energy-consumptive. The batteries also represent a significant additional cost, both in initial investment and maintenance. Batteries capable of storing enough energy to power all the functions of a typical home are quite expensive and need to be replaced every few years. Furthermore, the batteries contain large quantities of heavy metals such as lead, making them an unattractive option for the environmentally conscious homeowner and posing a potential health risk to the home's inhabitants. From an environmental perspective, the effects of this toxic composition and the highly energy-intensive production process make battery backup a less-than-ideal option. For our purposes, battery backup should be considered only in the case of a homeowner who specifically requests this technology.
Solar Hot Water systems rely on the same basic concept of other PV systems - they absorb energy from the sun and convert it for common household use. Instead of converting it to electricity, solar hot water systems use that energy to heat water. There are a number of different types of solar hot water systems, ranging from the rudimentary to the complex. The most basic systems simply circulate water through a series of pipes that are exposed to sunlight, heating the water through simple radiation. Because of the climate in our market, these systems have application only for seasonal demands, but may still be valuable for specific installations like outdoor showers, pools, or spas. They also represent the lowest end of the cost spectrum for solar hot water. Sometimes known as open-loop, direct, or passive systems, they provide little or no utility when cloudy conditions or freezing temperatures are common.
No, solar power systems are compatible with the electric grid. If the solar power system is not meeting the electric demands of the residence, electricity from the grid automatically makes up for the difference. There are, however, specific installation requirements for connecting the system to your grid.
Sometimes the solar power system will not be able to produce the amount of electricity demanded by the resident, the electric utility grid will compensate for this. Other times, it will produce more electricity then is being used by the household. Net metering allows households to sell the excess energy produced by their solar power system. These households only pay for electricity use that is not covered by their solar power system.
Solar power systems are compatible with most homes where direct sunlight is available. Typically a sunny place on the roof is needed that measures about 120 square feet for smaller systems and up to 1,000 square feet for the largest system. Eliminating shade from trees or other obstructions will enhance the functionality of the installation. A south-facing roof area is most recommended, though panels can be mounted on west- or east- facing roofs and still create more than 90 percent of the power of a south- roof mounting.
It is important to understand your electricity usage to determine the necessary capacity for your solar power system. This can be determined by studying your utility bill, which has a summary of how much power you have used each month for the past year. Residential systems range from as small as 500 watts to 10,000 watts, though they typically average between 2,000 to 5,000 watts. Most residential units are connected to the utility power grid for backup. Fontenot Contracting can help assess what kind of system would be most ideal for your home.
Federal tax credits amount to 30% of the solar power system. Also, some mortgage lenders offer energy efficiency mortgages that take into account the value added to the residence by the system installation. Additionally, some solar power systems and solar financing companies offer third party financing or solar leasing options.
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When doing more extensive renovations, other considerations may include:
Because water is a finite resource, efforts should be made to promote the efficient use of available water resources while maintaining sufficient water quality. Rainwater harvesting provides an economical, sustainable and reliable alternative water source. Rainwater harvesting is the process of accumulating and storing rain. Rain is generally collected from roofs and subsequently stored in catchment tanks that can be above or below the ground. Rainwater harvesting systems range from the small-scale, manually run systems to the large-volume, multiple tanks and controls. If the rainwater runs dry, municipal or well water can be used as a backup source. Having a rainwater harvesting system can significantly reduce water supply costs as well as help protect one of the earthís most valuable resources.
Decreasing potable water use decreases water fees on both water and sewer bills.
Non-potable purposes include (Water does not require chemical treatment):
Potable purposes include (Water needs to be chemically treated):
Besides its many practical uses, captured rainwater protects the environment by diminishing rooftop runoff which causes nonpoint source pollution. Rainwater harvesting systems have a long-term effect on local water resources in that they reduce demand for groundwater and surface removal. They also preserve local water sources by decreasing the amount of polluted rainwater that flows into them. Potable water uses more resources to treat, store and transport. Using an onsite source for water reduces the carbon footprint because water is not treated and transported. Treatment and transport are both energy intensive.
The components of a complete rain harvesting system include the catchment are (a roof), conveyance system which directs the water (gutters and leaders), holding vessels (cisterns), a roof-washing system (the first ten to twenty gallons of rain are diverted from the cistern), a delivery system (pumps) and a treatment system (filters and/or purifiers).
System can be custom designed or purchased as a package. The parts can be added by retrofitting existing gutter/ladder and roof systems. The best choice for rainwater catchment is uncoated stainless steel or galvanized steel with a baked-enamel finish that is certified as lead-free.
Rain harvesting systems vary from the simple to the complex. Rainwater is used immediately with simple systems. These systems can be designed to meet the needs of the existing site. Designing rain water harvesting systems into new constructions allows homeowners more elaborate and thorough development options. With very simple systems, the pay back period may be almost immediate.
In our Markets, Fontenot Contracting does not recommend that rainwater be captured for potable use.
When the collected rainwater is to be utilized for human consumption, roof washing is a viable solution to collecting and disposing the first flush of water which contains the most contaminants. Water that is used for laundry and dishwashing may need to have its pH levels adjusted or unwanted minerals filtered out. It is necessary to disinfect the water if it to be used for bathing, drinking, and cooking. Ultraviolet water disinfection units are the preferred method because they eliminate most microorganisms. Chlorine is another common disinfectant because it is dependable, water soluble and readily available.
The installation effort is contingent on whether the roof and/or drainage system needs to be replaced or altered, which can be determined by checking the composition and condition of the roof and/or drainage system, and the intended purpose of the water. Most of the parts are simply bolt-on. For example, a roof-wash system is relatively simple to attach to a gutter.Key considerations pertaining to roofs:
EPA MA State Reuse Regulations and Guidelines (see page 14)
Roof square footage x .623 gallons per square inch of rainfall x annual rainfall. Where does the .623 come from? Square footage of the roof of the house x amount of rain and the last variable is .623. A cubic foot of water equating to 7.48 gallons, which when divided by 12 (inches to a foot) equals .623 gallons per inch of rain.
From 2003 to 2008, the average cost of water in the United States rose 29.8%. Prices are expected to keep increasing due to rising costs to treat water to comply with EPAís Safe Drinking Water Act guidelines, upgrade declining infrastructures, and install conservation programs.
According to the US Environmental Protection Agency, an average of more than eight billion gallons of water is used for lawn and landscape irrigation daily. This amounts to about 1/3 of residential water use. Having a rainwater harvesting system can significantly reduce water supply costs.
The price varies significantly depending on the chemical content on the roof, and the roof itself, as well as the end use of the water. A complete system with sophisticated filtering and purification parts can cost over $20,000, whereas as a simple system used only for irrigation may be $3000 to $4000.
Most of the cost is upfront, but well-maintained systems usually pay for themselves within a few years. Furthermore, the systems have minimal maintenance costs. Some municipalities, such a Newton, charge sewer rates potable water usage. Rates were raised in 2009 and are being significantly raised in 2010.
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More technology and figures, including estimated irrigation installation requirements: Sustainable Resources