http://www.neutralexistence.com/index.php/begreen/ en bjmcconnell@alltel.net Copyright 2008 2008-05-01T15:21:00-06:00 http://www.neutralexistence.com/site/geothermal-exchange-ground-source-heating-and-cooling/ http://www.neutralexistence.com/site/geothermal-exchange-ground-source-heating-and-cooling/#When:04:55:00Z Geothermal ground-source heating and cooling, technically known as geothermal exchange, is the process of harnessing the earth’s constant underground temperature to heat and cool a structure. The term geothermal exchange really describes the process of exchanging heat energy with the earth. Throughout the world, while above ground air temperatures vary drastically between sub-zero and over 100°F, the earth’s temperature 6 feet below grade remains relatively constant and only varies between 50°F and 70°F. This is due to the fact that the earth is a thermal mass and has thermal inertia otherwise known as Volumetric heat capacity. This thermal inertia provides a constant source of energy which can be used effectively to heat and cool a building or residence. All geothermal exchange systems use devices called heat pumps. Heat pumps are extremely efficient at heating and cooling due to the fact that they move heat as opposed to generating heat. A typical HVAC system will use gas or electricity to generate heat in the winter and remove heat and moisture in the summer. This type of setup will never exceed 100% efficiency because you only get out what you put in. On the other hand, a heat pump, because it simply moves heat can effectively provide 4 times the heating and cooling with the same unit of energy used in a typical HVAC system. That means that in certain conditions, heat pumps can see efficiencies in excess of 400%. The only drawback to typical air exchange heat pumps is that when interior and exterior temperature differentials exceed 30°F, they have a hard time keeping up. For instance, when the outside air temperature is below 0°F, it is nearly impossible for a heat pump to move heat from that condition into the home, and it is for this reason that typical air exchange heat pumps come fitted with supplemental heaters for cold winter days. This drawback can be solved by using a geothermal exchange setup as opposed to an air exchange setup. As stated above, the sub surface temperatures of the earth stay relatively constant throughout the year, so these ground source heat pumps never see 30°F temperature differentials. Geothermal exchange systems come in many different types, sizes and configurations, but all of them have have two main components, the heat pump and the ground loop. There are basically two types of geothermal exchange ground loop systems, an open loop system and a closed loop system. Open Loop Geothermal Exchange System: An open loop system is quite uncommon due to the fact that it relies on a nearby body of water( stream, pond, lake or underground well). In an open loop system, the water from the body of water flows (underground) to the heat exchanger in the heat pump and then back out again. This type of system is slightly more efficient than a closed loop system because the source water comes into direct contact with the heat exchanger. In a closed loop system, the water or antifreeze circulating in the plastic pipe is isolated from the ground temperature, so the heat exchange is slightly less than in an open loop system. Closed Loop Geothermal Exchange Systems: Closed loop geothermal exchange systems, unlike open loop systems, use an environmentally friendly antifreeze liquid to exchange the heat between the earth and the heat exchanger in the heat pump. A closed loop system is the most common type of geothermal exchange system simply because it does not require a nearby body of water to pull from. Closed loop systems come in a variety of different configurations all of which have their own benefits and detriments. Vertical Loops: Vertical loop configurations are the most expensive of all of the closed loop configurations due to the fact that large well holes must be drilled down to a suitable depth, piped and then filled with a thermal grouting compound. These types of closed loop systems are ideal for areas where yard space is limited and the required area needed to cool the structure with a horizontal closed loop system is exceeds what is available. Also, in situations where the earth is rocky close to the surface or when the geothermal exchange system is retrofitted to an existing structure and limited land disturbance is required, the vertical loop configuration is perfect. The number of vertical drill wells is directly related to the depth of the wells, in other words, less holes for deeper wells. The depths of the drilled holes will generally vary between 150 to 450 feet where they will ultimately depend on the needs of the structure as well as the cost. Horizontal Loops: Horizontal closed loop configurations are the most popular and most cost effective of all geothermal exchange systems. Horizontal loops require the use of a trencher or a backhoe to dig to a depth of at least 8 feet. Individuals who are able and willing to do some of this work themselves can see a drastic reduction in the total cost of their geothermal exchange system. As a rule of thumb, a typical horizontal loop system will require 400 to 600 linear feet per ton of cooling capacity. Another type of horizontal configuration is the slinky loop. While a slinky loop will require less land area, it will generally require more pipe than a typical parallel type horizontal loop configuration. As with a parallel loop, the earth is excavated to a depth of approximately 8 feet and the pipe is coiled like a flattened slinky and then buried. Pond Loops: In specific situations, where an open loop system cannot be applied to a nearby body of water, a closed loop system may be the best choice. Just like the other closed loop systems, an environmentally friendly antifreeze is circulated through the closed polyethylene piping except the exchanging medium is water instead of the earth. Bodies of water, like earth are thermal masses and hold the same thermal inertia as the earth does, so at the same depth, the body of water will provide very similar constant temperatures as the earth. Pond loop configurations are generally slinky like in nature and extend a minimum of 6 to 8 feet below the the lowest water level to assure proper heat exchange. Heat Exchanger Variations: There are two basic ways of exchanging the heat from the earth to the heat exchanger inside the heat pump, using a fluid to water heat exchanger or a fluid to air heat exchanger. In both cases, the fluid refers to the water or antifreeze in the ground loop and the water or air refers to the medium used within the structure as the delivery method. In a fluid to water heat exchanger, the water in the structure is typically used for radiant heating and cooling where the floor and/or walls act as thermal masses with the water lines embedded inside. In a fluid to air heat exchanger, the air within the structure is typically ducted, using conventional ducting methods to the spaces throughout the structure. The delivery method really comes down to the preference of the end user, however, fluid to air exchangers will typically cost less due to the fact that ducting is less labor intensive than laying radiant flooring. Another heat exchanger variation is the use of supplemental heat to generate your domestic hot water. In the summer, when the heat pump is moving heat from within your home, that excess heat can be used to generate your domestic hot water for free. During the winter when the heat pump is moving heat from outside to inside, the extra heat generated from the actual heat pump motor can be recovered and used to generate your domestic hot water very efficiently, but not free. Geothermal exchange systems are extremely efficient, cost effective heating and cooling systems and can be used in almost any environment. These ground source systems can reduce energy cost by up to 60% when compared to typical HVAC system of equal tonnage. Although most geothermal exchange systems will cost more up front, if those cost are added to the mortgage, the monthly energy savings will generally offset the added mortgage cost each month. Not only can these geothermal exchange systems save money, but because of their efficient nature, they will help the environment by reducing your energy consumption. Green Your Buildings, Energy and Atmosphere 2008-03-08T04:55:00-06:00 http://www.neutralexistence.com/site/green-building-introduction/ http://www.neutralexistence.com/site/green-building-introduction/#When:23:02:00Z Green building encompasses a very large field of expertise, all of which focus on increasing efficiency and establishing to some degree, some form of sustainability. Green builders accomplish this by using a variety of techniques ranging from natural building techniques, rainwater harvesting, energy harvesting, better siting and placement, more efficient design and construction methods, and better materials. Green building which is thought to be synonymous with sustainable design and environmental building, will generally produce similar benefits such as reduced environmental impacts, lower electricity and water usage, less operating cost and also improved indoor air quality causing better occupant health and well being. Unlike natural building, green building is heavily focused on creating aesthetic harmony with the surrounding environment, while remaining a positive ecological presence. Because of this, most green buildings and homes are often indistinguishable from other non-sustainable inefficient buildings and homes. Leadership in Energy and Environmental Design (LEED) Green building is governed by standards, such as the Leadership in Energy and Environmental Design (LEED) standards developed by the U.S. Green Building Council. LEED certifications is essentially a standard point system on which homes and buildings are graded and given a rankings. These rankings reflect the degree of “greeness” of each structure, and ca be used to receive federal tax credits and other state funded benefits and incentives. The ranking of LEED certified structures is directly related to the degree of energy efficiency of the structure, which will generally result in below average energy cost for the structure. Natural Building vs. Green Building Natural building, although different from green building shares similar goals and ideas. Natural building focuses on using natural local materials and construction types to minimize the environmental impact. In general, natural building is more suited for homes than for buildings, as many of the techniques and materials are not suitable for multi story structures nor will they meet local and international building codes. the commonalities between natural building and green building is that both place a very high value on using local materials and efficient construction techniques, although green buildings tends to be much more refined and “systems” oriented. Green building design encompasses the following areas: 1: SUSTAINABLE SITES a. Site Location and Linkages * Site selection * Site usage and disturbance * Flood zones * Urban/rural * Utility capability * Site infill’s * Shared boundaries b. Site orientation, shading & Landscaping * Existing vegetation * Recycled site material * Natural/existing shading * Shading of hardscapes(pavement) * Maximize green spaces * Drainage * Irrigation techniques * Plant selection * Drought resistant plants * Grass/plant ratio - little grass * Deciduous trees 2: WATER EFFICIENCY * Water Reuse ----Cisterns ----Recycled water - washing machine ----Roof runoff collection * Irrigation System ----Recycled gray water * Indoor Water Use ----Wells and pump stations --- Efficient faucets, shower heads, toilets ----Dry systems/low flush 3: ENERGY & ATMOSPHERE * Energy star products * Insulation * Air Infiltration * Windows ----window orientation ----window types * Heating and cooling distribution ----Thermal cooling/heating ----Natural heating - trombe wall ----Natural cooling - tall windows ----Volume - high ceilings * Space heating and cooling ----Geothermal products ----Heat exchangers ----HVAC systems * Water heating ----passive ----tankless * Lighting ---- Low volt lightings ----Natural lighting ----Solar exterior lighting * Alternative energy ----Solar arrays ----wind turbines 4: MATERIALS & RESOURCES * Construction Types * Material usage/selection * Recycled material * Area ratio * Windows/doors * High Radiant barrier * Reflective roofing - metal * Durability * Labor friendly * Local materials * Roof top gardens 5: INDOOR ENVIRONMENTAL QUALITY * Air Filtration * Moisture control * Combustion Venting 6: INNOVATION & DESIGN PROCESS Green Your Buildings 2008-01-01T23:02:00-06:00