2010 Envisci Paper Gshp

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    GROUND SOURCE HEAT PUMP AS AN ALTERNATIVE IN HVAC SYSTEMS FOR

    BUILDINGS IN NUEVO LEON, MEXICO

    Hctor Miguel Hernndez TurrubiatesCenter for Environmental and Research Education, Duquesne University.

    600 Forbes Avenue, Pittsburgh, Pennsylvania, 15420, U.S.A.

    (412) 482-4913hernandezturrbh@duq.edu

    ABSTRACT

    The energy consumed in buildings represents an important part in generation of greenhouses gasesaround the world. The major part of energy consumption in buildings is due to Heating, Ventilation,and Air Conditioning (HVAC) systems.

    The use of renewable energies as an alternative for reduction of fossil fuels consumption is more oftenin the race for stop climate change. Geothermal energy has been gaining terrain the last years in HVACsystems through Ground Source Heat Pump (GSHP). However, in Mexico there is still muchuncertainty with this application because there is no much information or background on these issues,making it difficult to decisions makers, in building projects, to give an opportunity to GSHP systems.

    This paper aims is to analyze GSHP systems and its applications versus conventional HVAC systems.For this case of study, a typical building located in Monterrey, Nuevo Leon, Mexico, will be studied;taking into account variables that have an influence in the process, using computer's simulation tools.

    INTRODUCTION

    CURRENT AND FUTURE ENERGY SCENARIO IN MEXICODay after day not only growing demand for electricity use around the world but also the need to meetthose needs in a reliable, efficient and taking into account the care of the environment. Each countrydevelops its own strategies of power supply based on their economic development.

    The annual growth rate (AGR) of global electricity consumption for the period 1994 to 2003 was 3%.In North America the AGR has been 2%, below the world average; taking to Canada, United States andMexico an AGR of 1.4%, 1.9% and 5.7% respectively. The forecasts for world consumption areexpected that developing countries are those who achieve the highest growth in electricity capacity inthe coming years.

    In Mexico, electric service is in charge of the company Comision Federal de Electricidad(CFE) and itis this institution that regulates, through the Public Service Act Electricity (LSPEE) and EnergyRegulatory Commission (CRE ) all matters concerning the generation, transmission and distribution ofelectricity in the country. The power supply is classified into five areas: Agricultural, Industrial,Residential, Commercial and Services. The Industrial sector is the most AGR presented with a 4.5%during the period 1994 to 2004, and accounted for 59.1% of total domestic supply for the past year.However, this sector is divided into two sub sectors, Big Industry and Medium Enterprises, which

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    accounted for 38.8% and 61.2% respectively of the total industrial sector. The residential sector is insecond place, accounting for 24.9% of total consumption of generation in the country.

    Although only one institution is responsible for the electricity service in Mexico (CFE), it is dividedinto regions to better control. The Northeast Region has the highest growth has been in recent years interms of power consumption, with 5.2% AGR. This is mainly due to the number of new industries andhigh temperatures in this region, increasing the use of air conditioning and refrigeration.Nuevo Leon is one of the states that belong to this region and is the largest consumer of electricity with35% of the total energy supplied. The Projected growth in power in Mexico for 2015 is 5.2% AGR,with the Industrial Sector the fastest growing today.

    Unfortunately, the use of renewable energy technologies have a major development in our country inthe coming years, compared with natural gas which is estimated to cover 51.8% of the source ofelectrical energy production by 2014. This national strategy and concern about the current problems inthe environment, including climate change, makes us think of new ways to optimize the efficiency ofenergy end use. Buildings consume most of the energy industry and that is where we can find a goodarea of opportunity. The energy consumption in the operation of buildings is mainly due to heat gain bythe low level of thermal insulation envelope, causing a greater demand for cooling. The work on theoptimization of the thermal insulation of buildings is nothing new. But the use of alternative energytechnologies for cooling them is becoming increasingly common around the world. In this paper, weanalyze the potential of geothermal heat pumps (GSHP) as an alternative to the buildings in NuevoLeon.

    GSHP Ground Source Heat Pumps.

    FIGURE 1.- Schematic Draw of a GSHP system for a house.

    Ground Source Heat Pumps are electrically powered systems that tap the stored energy of the greatestsolar collector in existence: the earth. These systems use the earths relatively constant temperature toprovide heating, cooling, and hot water for homes and commercial buildings.

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    FIGURE 2.- Measurement of temperatures for different depths.

    GSHP can be categorized as having closed or open loops and those loops can be installed in threeways: horizontally, vertically, or in a pond/lake. The type chosen depends on the available land areasand the soil and rock type at the installation site. These factors will help determine the most economical

    choice for installation of the ground loop.For closed loop systems, water or antifreeze solution is circulated through plastic pipes buried beneaththe earth's surface. During the winter, the fluid collects heat from the earth and carries it through thesystem and into the building. During the summer, the system reverses itself to cool the building bypulling heat from the building, carrying it through the system and placing it in the ground. This processcreates free hot water in the summer and delivers substantial hot water savings in the winter.

    FIGURE 3.- Closed loop system.

    Open loop systems operate on the same principle as closed loop systems and can be installed where anadequate supply of suitable water is available and open discharge is feasible. Benefits similar to theclosed loop system are obtained.

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    FIGURE 4.- Open loop system.

    APPLICATIONS

    GSHP systems can be applied for both heating and cooling for buildings, pools, to melt snow and ice,and also for industrial process.

    Residential

    A GSHP system can be installed in a residential structure of any size, anywhere, whether it is single-family or multi-family. GSHPs can be installed on almost any size lot: under lawns, landscaped areas,driveways, or the house itself. An existing house can be retrofitted with a GSHP using the ductworkthat is already there. Your dealer/installer will be able to determine ductwork requirements and if anyminor modifications are needed. Home builders and homeowners can both take advantage of thespecial financing that is offered in many locations on a GSHP either through the utility or manufacturer.The Department of Energy (DOE) and the Environmental Protection Agency (EPA) have both endorsedground source heat pump systems as among the most energy efficient and environmentally friendly

    heating, cooling, and water heating systems available. In a 1993 report, the EPA concluded thatgeothermal technologies represent a major opportunity for reducing national energy use and pollution,while delivering comfort, reliability and savings to homeowners.

    HOPE CROSSING, Oklahoma.

    Hope Crossing is a 217 home development by Central Oklahoma's Habitat for Humanity (COHFH) inOklahoma city. This is a showcase large-scale demonstration of affordable low-energy housing and allthe houses will be certified in LEED by USGBC. The project utilizes ground source heat pumps, low-energy building construction techniques and solar energy consumption by 60 to 80 percent from currentpractice.

    GSHP systems provide homeowners with year-round comfort in a mixed-humid climate area of thecountry that presents substantial humidity throughout the year and requires significant heating andcooling. GHSP systems also provide high-efficiency performance and much lower utility bills,increasing the affordability of the homes.

    GSHP Benefits: Lower utility costs: The GSHP system is projected to save 50 to 75 percent of the traditional

    heating and cooling costs. Improved comfort: Residents have the benefit of heating and cooling from the quit and clean

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    geothermal system. Reduced maintenance: Since there is no outdoor equipment, damage from weather is

    eliminated. All routine maintenance performed inside. Vandalism: All equipment is located inside, minimizing the risk of vandalism and theft.

    Commercial

    GSHPs are a cost effective, energy efficient, and environmentally friendly way of heating and coolingbuildings. Both the DOE and the EPA have endorsed the technology. GSHPs reliably deliver qualityair-conditioning and heating, on demand, in every season. GSHPs are appropriate for new constructionas well as retrofits of older buildings. Their flexible design requirements make them a good choice forschools, high-rises, government buildings, apartments, and restaurants--almost any commercialproperty. Lower operating and maintenance costs, durability, and energy conservation make GroundSource Heat Pumps the smart choice for commercial applications.

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    SOILS CLASSIFICATION IN MEXICO.

    According to the National Institute of Geography and Statistics (INEGI) in Mexico the s