For the new office building, I am designing for a client who is a speculative building developer. With this factor in mind, I must design and develop this building at the lowest possible price with a low first cost which initially maximizes the profit of this building. This office building that I am developing is a 10 story office building. When getting into larger HVAC system applications, one must start looking at split-system units. A split-system air conditioner splits the hot coils from the cold coils of the system. The cold coils, consisting of the expansion valve and the cold coil, is generally placed into a furnace or an air handler. The air handler blows air through the coil and routes the air throughout the building using a series of ducts. The hot side, known as the condensing unit, lives outside the building. Inside the hot coil is a fan, to blow air through the coil, along with a weather-resistant compressor and a control logic to manage the temperature and pressure going throughout the coil. This approach has evolved over the years because of its low-cost and also it normally results in reduced noise inside the house. However, there is no difference between a split-system and a window air conditioner other than the fact that the hot and cold sides are split apart and the capacity is higher, making the coils and compressor larger which eventually makes the selection of a split system unit a better decision. When dealing with large buildings such as warehouses, large business offices, malls, big department stores and other sizeable buildings, the condensing unit normally lives on the roof and can be quite massive. Otherwise, there may be many smaller units on the roof, each attached inside to a small air handler that cools a specific zone in the building. Although standard air conditioners are very popular, they can use a lot of energy and generate quite a bit of heat. For large installations like office buildings, air handling and conditioning is sometimes managed a little differently. With this in mind, the split-system approach begins to run into problems. Either running the pipe between the condenser and the air handler exceeds distance limitations and starts causing lubrication difficulties in the compressor and more usage pressure through the pipes to run the system efficiently or the amount of duct work and the length of ducts become unmanageable. At this point, it's time to think about a chilled-water system. In a chilled-water system, the entire air conditioner is installed on the roof or behind the building. It cools water to between 40 and 45 degrees Fahrenheit. The chilled water is then piped throughout the building and connected to air handlers. This can be a versatile system where the water pipes work like the evaporator coils in a standard air conditioner. When it is well-insulated, there's no practical distance limitation to the length of a chilled-water pipe. However because of rising electrical costs and environmental concerns, some other air cooling methods are to be used. An option to use on this new office building is geo-thermal heating. It varies, but at around 6 feet (1.8 meters) underground, the earth's temperature ranges from 45 to 75 degrees Fahrenheit. The basic idea behind geo-thermal cooling is to use this constant temperature as a heat or cold source instead of using electricity to generate heat or cold. The most common type of geo-thermal unit for an office is a closed-loop system. Polyethylene pipes filled with a liquid mixture are buried underground. During the winter, the fluid collects heat from the earth and carries it through the system and into the building. During the summer, the system reverses itself to cool the building by pulling heat through the pipes to deposit it underground. Due to the rising costs of electricity and the trend to "go green," is the most effective decision to make is by turning to alternative cooling method to spare money and also the environment. One way the office building can save on energy cost is by installing geo-thermal heating and cooling systems, also known as ground source heat pumps (GSHP). Geo-thermal units are the most energy-efficient and environmentally sensitive of all space conditioning systems. The basic principle behind geo-thermal cooling is to use this constant temperature as a heat source instead of generating heat with electricity. The speculative building developer can save up to 30 to 50 percent on their cooling bills by replacing their traditional HVAC systems with ground source heat pumps. The initial costs can be up to 30 percent more, but that money can be recouped in three to five years, and most states offer financial purchase incentives. Another benefit is that the system lasts longer than traditional units because it's protected from the elements and is immune to theft. This selection would differ from designing a building for an institutional building developer due to fact that an institutional building requires a low operating cost. Therefore, a water source heat pump would be a better selection for the institutional client. A Water Source Heat Pump (WSHP) system is one of the most efficient, environmentally friendly ways to heat and cool buildings because each unit responds specifically to the heating or cooling load of the individual zone it serves. These systems are ideal for larger building infrastructures – the institutional office building. The benefits are outstanding - excellent comfort, better efficiency and lower operating costs. A water source heat pump system shares the ability to move energy from where it is not needed to where it is needed with other sophisticated HVAC systems. The energy is moved in water, which is very effective and requires minimal transport (pump) work. Other HVAC systems capable of moving energy around a building include fan assisted VAV and dual duct, dual fan VAV. However, these systems move the energy in air rather than water, which requires ceiling plenums, ducts and fans. In a WSHP system, high efficiency, self-contained units can be placed in virtually any location within a building and connected via a water loop. Heat is added and rejected from the loop using a boiler and cooling tower, or by using natural sources such as the ground, a well or a pond. In this case, the water source would be extracted from a well which is built underground near the institutional building. Each unit responds only to the individual cooling or heating load of the individual zone they serve. This results in close control over the temperature and humidity in each building zone, which leads to excellent occupant comfort. Energy use is kept to a minimum because units will generally only operate when there is a call for heating or cooling in their specific zone. In fact, in warmer environmental conditions, the units may operate for only a short period of time during occupied hours. Systems that cannot move energy around the building tend to use electricity to cool one part of the building, and natural gas or another source to heat other parts of the building. While they are not necessarily simultaneously heating and cooling a specific space, the overall building experiences simultaneous heating and cooling. Geothermal (ground-source or water-source) heat pumps achieve higher efficiencies by transferring heat between the institutional building and the ground or a nearby water source. Although they cost more to install, geothermal heat pumps have low operating costs because they take advantage of relatively constant ground or water temperatures.