Home Inspection FYI

Providing Help, Knowledge and Other Useful Information To Home Owners Everywhere

Home Inspection FYI - Providing Help, Knowledge and Other Useful Information To Home Owners Everywhere

Disadvantages of Solar Energy

Solar Energy Does Have Some Disadvantages

While the considerable advantages offered by solar energy move some renewable energy proponents to ignore the budding technology’s comparatively minor flaws, these imperfections must be acknowledged, lest their resolutions be stalled. We should take an honest look at the system’s disadvantages and seek to refine solar energy systems into a truly environmentally friendly renewable energy. The most significant complaints with solar energy are:

  • Lack of consistency and reliability. Solar systems rely on the steady absorption of sunlight — particularly, subatomic particles called photons – which can be easily deterred. The following factors limit the availability of sunlight:
  • Altitude. Although solar power is an option almost anywhere on the planet in at least some capacity, efficacy falls sharply as distance from the equator increases. Residents of Vancouver, Canada, and St. Petersburg, Russia, for instance, are at a significant solar disadvantage.
  • Clouds. Clouds diminish the power of solar panels, especially in habitually foggy or overcast regions. According to the National Renewable Energy Laboratory, “The solar resource during foggy or low-cloud conditions is approximately 10% of the value under clear-sky conditions.” Solar arrays in Denver, Colorado, would rarely be obscured by clouds, as that city experiences only 30 to 40 overcast days per year. Hilo, Hawaii, despite its proximity to the equator, receives rain an average of 277 days per year, which might make it a poor choice for solar-power generation.
  • Night. The Earth itself is a rather large obstruction, and it acts nightly to disturb the flow of photons to helplessly immobile solar arrays. clouds Disadvantages of Solar Energy
  • Size. To power an entire building, a large solar array is required. It’s unfortunate that photovoltaic technology is still in its infancy but, for now, we must build large arrays to compensate for the inefficiencies of single solar panels. A bulky mechanical orientation can be ineffective in gathering solar power.
  • That Bulky system may also be required to turn the panels as they follow the sun across the sky. Batteries, too, can take up a fair amount of space.
  • Panel deterioration. Like anything else left out in the sun, solar panels gradually become damaged by ultraviolet radiation. Rain, snow, dirt, temperature fluctuations, hail and wind also pose serious hazards.
  • Cost.  The number of solar array panels needed to capture energy for an entire home typically costs tens of thousands of dollars, making the electricity they produce cost substantially more than that provided by conventional power sources. Solar power proponents quickly point out the considerable local and state government subsidies and tax credits, which essentially divert the financial burden to taxpayers. Another consideration is that the expansive battery banks needed for solar arrays are typically not covered under the warranty for the panels themselves. They also don’t last nearly as long as the panels, and it may cost $100 or more for each battery’s replacement. Solar panels, however, are getting more affordable and efficient as the renewable energy technology develops, perhaps to the point where un-subsidized solar power will be more affordable than conventional coal, gas, nuclear or hydroelectric energy sources.
  • Environmental pollutants. A few of the more notorious substances contained in panels and associated equipment include:bat Disadvantages of Solar Energy
  • Cadmium. When sealed inside solar panels, cadmium is harmless. If leaked from the panel, cadmium can inflict serious environmental damage. Panels must be disposed of with extreme care in order to keep this carcinogenic substance from leeching into soil and water.
  • Lead. Batteries, specifically deep-cycle, lead-acid batteries, are required by solar arrays to ensure a constant supply of electricity. They contain lead and sulfuric acid, which are both highly toxic, especially to marine creatures. Lead has been found to cause a number of impairments in children, including developmental disabilities. However, most of the material in dead batteries is recoverable if the batteries are recycled, as long as consumers make the effort.
  • Roof considerations. Solar arrays are often installed on building roofs to make use of the large, empty, sunny space. As a consequence, repairs to the underlying roof become quite tricky and often require disassembly of the solar installation before even routine roof maintenance can be performed. It’s good practice to perform needed roof work before the initial installation of a solar system to prevent future headaches.
  • Appearance. Like it or not, solar arrays speak loudly, and neighbors and passersby will take notice of the systems. Many homeowners are understandably reluctant to install a large solar array on an otherwise attractive tile roof. This issue is being addressed through the development of photovoltaic shingles, windows, and other technologies that blend more seamlessly with existing roof surfaces.

FYI, residential solar power has some aesthetic, economic and technical drawbacks, but many of them can be overcome by planning and responsible maintenance in the development of the type of renewable energy. 

Geothermal Heating and Cooling Systems

Geothermal Systems For Home Heating and Air Conditioning


Geothermal systems are home heating and cooling systems that gather heat from the earth. Geothermal heat pumps (GHPs) use the relatively constant temperature of sub-surface soil as the exchange medium.geothermal home Geothermal Heating and Cooling Systems

Geographical Distribution
  • As of 2004, five countries — El Salvador, Kenya, the Philippines, Iceland and Costa Rica — generate more than 15% of their electricity from geothermal sources. In Iceland, geothermal energy is so cheap that some sections of pavement are heated.
  • In the United States, roughly 50,000 geothermal heat pumps are installed every year. The U.S. leads the world in geothermal exploitation.
  • The combined production of geothermal energy for all uses places third among renewable energy sources, following hydroelectricity and biomass, and ahead of solar and wind.

Where does geothermal energy come from?

Beneath the Earth’s crust, there is a layer of hot, molten rock called magma. Heat is continually produced there, mostly from the decay of naturally radioactive materials, such as uranium and potassium. The amount of heat within the first 33,000 feet (or 10,000 meters) of the Earth’s surface contains 50,000 times more energy than all the oil and natural gas resources in the world combined.

Benefits of Geothermal Energy:

  • energy efficiency. GHPs require 25% to 50% less electricity than conventional heating and cooling systems. According to the EPA, geothermal heat pumps can reduce energy consumption — and corresponding emissions — up to 44%, compared to air-source heat pumps, and up to 72%, compared to electric resistance heating with standard air-conditioning equipment.geothermal closed loop vertical Geothermal Heating and Cooling Systems
  • design flexibility. Geothermal heat pump systems can be installed in both new and retrofit construction. Equipment rooms can be scaled down in size because the hardware requires less space than is needed by conventional HVAC systems. GHP systems also provide excellent “zone” space conditioning, which allows different parts of a home to be heated or cooled to different temperatures.
  • durability. Since GHP systems have relatively few moving parts and the parts are sheltered inside a building, the systems are durable and reliable. The underground piping often carries warranties of 25 to 50 years, and the heat pumps can last more than 20 years. The components are easily accessible, which helps ensure that the required maintenance is performed on a timely basis.
  • noise reduction. As they have no outside condensing units (such as those in air conditioners), there’s no noise outside the home. Geothermal heat pumps are so quiet inside of a house that users may not be aware they are operating.

How do geothermal systems work?

A geothermal heat pump, unlike a furnace, does not create heat by burning fuel. Instead, it collects the earth’s natural heat through a series of pipes, called a loop, installed below the frost line. At that depth, which varies by climate zone, the soil remains at a relatively constant temperature throughout the year. Fluid circulates through the loop and carries heat to the house. There, an electrically driven compressor and a heat exchanger concentrate the heat and release it inside the home at a higher temperature, where ductwork distributes the heat to different rooms. In summer, the underground loop draws excess heat from the house and allows it to be absorbed into the earth. The system cools the home in the same way that a refrigerator keeps food cool — by drawing heat from the interior, rather than by forcing in cold air.geothermal closed loop pond lake Geothermal Heating and Cooling Systems

Types of Geothermal Systems

There are four basic types of geothermal systems. Selection of the most appropriate system depends on the climate, soil conditions, available land, and local installation costs at the site. All of these systems can be used for residential and commercial building applications. They include:

  • horizontal:  This type of installation is generally the most cost-effective for residential installations, particularly for new construction where sufficient land is available. The most common layouts use either two pipes (one buried at 6 feet, and the other at 4 feet), or two pipes placed side-by-side buried 5 feet in the ground in a 2-foot wide trench.
  • vertical:  Large commercial buildings and schools often use vertical systems because the land area required for horizontal loops is prohibitive. Vertical loops are also used where the soil is too shallow for trenching, and they minimize the disturbance to existing landscaping. For a vertical system, holes (approximately 4 inches in diameter) are drilled about 20 feet apart and 100 to 400 feet deep. Two pipes are inserted into these holes and connected at the bottom to form a loop. The vertical loops are connected to the heat pump in the building.
  • pond/lake:  A supply-line pipe is run underground from the building to a body of water and coiled into circles at least 8 feet under the surface. In order for the body of water to be adequate, it must meet minimum volume, depth and quality criteria.
  • open-loop system:  This type of system uses well or surface water as the heat exchange fluid that circulates directly through the GHP system. Once it has circulated through the system, the water returns to the ground through the well, a recharge well, or surface discharge. geothermal open loop well Geothermal Heating and Cooling SystemsThis option is practical only where there is an adequate supply of relatively clean water, which must comply with local codes and regulations regarding groundwater discharge.

Cost

A geothermal system usually costs about $2,500 per ton of capacity. A typical home uses a 3-ton unit costing roughly $7,500. That initial cost is nearly twice the price of a regular heat pump system that includes air conditioning. The cost of drilling, however, can be considerable; drilling can cost in excess of $30,000, depending on the terrain and other local factors. Systems that require drilling vertically deep into the ground will cost much more than systems where the loops are in a horizontal fashion and closer to the surface. Despite these initial costs, a geothermal system saves enough on utility bills that the investment is often recouped in five to ten years.

FYI, geothermal systems heat and cool homes using sub-surface soil as an exchange medium. Geothermal systems are more expensive to install than conventional furnaces, but their operating costs are significantly lower.

 

Geothermal Energy Information

 

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Radiant Heating Systems

Radiant Heating Systems for Floors and Walls

Radiant heating systems directly heat the floor or panels in the wall or ceiling of a house, rather than heating the air, as do forced-air
radiant heta system 201x300 Radiant Heating Systems heating systems. The radiant heating technique can be likened to standing in full sun on a chilly day, or feeling the warmth of a distant bonfire even though the air is cold. Despite their name, radiant heating systems also depend on convection — the natural circulation of heat within a room — caused by heat rising from the floor.

Radiant heating has been used since ancient times, perhaps as far back as 4000 BC in Mongolia. The ancient Romans, too, made use of a type of radiant heating known as a hypocaust to heat their houses and public baths. Recent decades have seen more mainstream use of radiant heating in Europe, although it is finally gaining popularity in the United States, especially in new-home construction, where installation of radiant heating is more economical.

Radiant heating systems use one of two heating mediums, each of which is described below:

  • water (hydronic) radiant heat: This system uses hot water carried by tubing, arranged in a grid, to heat the home.
  • electric radiant floors: This system uses electricity carried by cables or floor mats to heat the home.

An installation of a radiant heating system in a floor is either wet or dry (not to be confused with the aforementioned distinctions), and the decision to use one or the other is largely based on whether the system will be installed in new or existing construction. These two methods are briefly summarized as follows:

  • In a wet installation, the heating panels are installed on the floor, and a thin layer of concrete or gypsum is spread over the installation, sandwiching the cables or tubing between two layers of flooring or concrete. This installation is ideal in new-home construction, where a concrete slab, which has high thermal mass, is used to build the ground floor.
  • Radiant floor dry installations are relatively new strategies in which the cables or tubing run in an air space beneath the floor. Tubing is often sandwiched between layers of plywood or beneath the sub-floor. Dry heating is more common in retrofits and when the floors in new homes are not poured concrete.

Advantages of Radiant Heating

  • efficiency. Radiant heating systems use less energy than convective heating systems where the same fuel is being used. This is due to a number of reasons:
    • The thermostat can be set to a lower temperature and still afford the same comfort. Rooms heated by radiance are typically heated uniformly from floor and ceiling, in contrast with forced-air systems, which leave the floors cold. Studies conducted by the American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) indicate that people can be as comfortable at temperatures 6 to 8 degrees lower with radiant heating than with convective heating that uses air as the primary heat-transfer medium.
    • They require no ducts or pipes, which account for heat losses in other systems.
    • There is less heat loss through windows because air is not being blown.
    • Radiant heaters can be zoned so that energy is only used to heat individual rooms. You can thus more easily direct heat to areas that are more trafficked or chillier, while directing heat away from rooms that see little use.
  • Radiant heating systems, unlike forced-air systems, pose little threat of spreading dust, pollen and germs.
  • flexible fuel choices. Hydronic systems can be heated with a wide variety of energy sources, such as solar water heaters or gas, wood or oil-fired boilers.
  • unobtrusive. Radiant heating systems are not visible in the occupied space, which saves floor space and allows for more decorative freedom.
  • quiet and clean. Radiant heating systems are quiet, clean and require little or no maintenance. An oil-fired heating boiler, on the other hand, requires annual maintenance.
  • Radiant heaters take a long time to cool. This can be beneficial in several ways:
    • The heater can be run at night during off-peak hours when electricity rates are cheaper. It can then be turned off, yet still radiate heat, during peak hours.
    • As it takes a long time for radiant heaters to cool down, they will continue to provide heat for hours into a blackout.

Disadvantages of Radiant Heating

  • Additional under-slab insulation is required for radiant heating systems mounted on the ceiling.
  • limited choice of floor covering. Carpet, due to its properties as a thermal insulator, reduces efficiency of in-floor systems. Wood, too, may not be a good choice because of its tendency to crack or shrink when heated. If wood must be used, it is best to use wood with a low moisture level to avoid shrinking and gaps.
  • potentially high utility costs. In some areas, electricity is the most expensive way to provide heat.
  • high up-front cost. Due to their complex installation, up-front costs can be prohibitive.
  • long warm-up period. Electric radiant heating systems heat up faster than liquid systems, although both take longer than conventional forced-air systems.
  • They can only be used to heat. Separate radiant heating systems are required to provide cooling, air cleaning and ventilation. A forced-air system, by contrast, can do all of these things.
  • Maintenance and repair of pipes may be difficult due to their lack of accessibility.

FYI, radiant heating is an attractive alternative to conventional heating systems, although neither system is perfect.

 

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