An HVAC system is one of the main systems in a hotel property. While designing a HVAC system, there are extensive details to be considered. Among them are the three most important elements -energy conservation, water conservation and indoor air quality. Besides heating, ventilating, and air-con equipment, the whole HVAC system can be coupled with other systems especially control systems to ensure its efficiency. Several processes in planning for a successful HVAC system include designing, purchasing, operating and maintenance.
As hotels are businesses, the entire mission is to make profit. The basic principle of designing an HVAC system is to make it efficient. On one hand, hotels have to ensure guests' satisfaction and provide a comfortable work environment for employees. On the other hand, hotels also have to cut cost because HVAC system is a huge energy consumer.
Although retrofit of any HVAC system can be expensive, it will probably be worth it for hotels with old equipment. The investment will in actuality be covered in only couple of years and bring hotels many long-term benefits. Furthermore, a fresh HVAC system helps hotels to be socially responsible and protect the environment.
Introduction
HVAC (Heating, Ventilating, and AIR-CON) identifies the technology of indoor or automotive environmental comfort (Wikipedia). HVAC systems in hospitality buildings provide control of the inside temperature, humidity, air movement, and quality of air within the structure (Hotel Mule Wiki). A well-designed HVAC system is made up of a number of components including boilers, chillers, centralized and decentralized guestroom HVAC units, large roof mounted PTAC units, air handling units, and cooling towers. As service is core of the hospitality industry, an HVAC system directly influences guests' satisfaction and therefor plays a big role in ensuring hotels' success.
The needs associated with an HVAC system can be quite different with respect to the size, location, structure and design of the hotel property. A small B&B may only have a heating unit while a big luxury hotel may apply a huge temperature control system. Using the development of technology, some HVAC systems are extremely high-tech and efficient. Besides, the renovation of any HVAC system in a few old properties can be highly expensive and complicated. When planning an HVAC system, any small mistake may lead to a large failure and potentially a hotel disaster.
As HVAC system is a large consumer of energy, the more efficient they are, the more costs a hotel can cut. A "green" system can also help a hotel to build a good reputation. In such a paper, some suggestions and analyses of how to create a hotel HVAC system will be discussed.
According to Pradeep (2005), although designing an HVAC system for a hotel is a huge project and contains many key steps, the following three will be the most important:
* Energy conservation
* Water conservation
* Indoor air quality
Energy conservation
Unlike office buildings, HVAC systems have to be operated for 24 hours a day, seven days a week in hotels. As Hu, Kwong, and Chao (2006) argued, you can find room to save lots of energy in hotels. Deciding on a chilling unit, pumping system and cooling tower is vital to the control of energy use. Although chillers with higher Coefficient-of-Performance (COP) are more costly, they are suitable for hotel applications and the payback period is reasonable (Hu, Kwong & Chao, 2006). Predicated on this consideration, water cooled chillers should replace air cooled chillers.
Another way to boost cooling system efficiency is installing variable-frequency drives on chillers, pumps and cooling towers (Fypower). By using these drives, coolant system power loads can be managed to match hotels' specific needs; for example, the cooling load in summer could be much high than in autumn, the cooling load may be different between day and night. Therefore, sometimes it is not necessary for chillers to perform on a complete load on a regular basis. Hotels can save energy during the low cooling load period. Furthermore, larger hotels or convention centers may have another problem: the occupancy level can fluctuate significantly within a brief period of your energy. As Hu, Kwong, and Chao (2006) mentioned in their study, "Manual control might not respond fast enough and could cause waste of energy. " To deal with this, building automation systems (BAS) can be utilized. They are able to integrate, control and monitor HVAC equipment in a most effective way with minimum human errors (Pradeep, 2005).
Another part of the system is by using the free cool air from outside to save lots of energy. When a temperature sensor or web-based control system (Scarpa, 2009) can be employed by a hotel, it is even possible to get free cooling during the morning and evening.
Water Conservation
Water conservation in an HVAC system is much less important as in other functional utilization such as cooking, washing, bathing, flushing, laundry and boilers, etc. (Pradeep, 2005). If hotels use water cooled chilling units rather than air cooled chillers, they will consume a huge amount of water. But as the quality of water for cooling towers is much lower than potable water, hotels can resolve this problem by utilizing a gray water system or properly reusing sewage water.
Indoor Air Quality
The "V" in HVAC system refers to ventilation. Through the process of ventilating, air can be changed or replaced in any space to regulate temperature or remove moisture, odors, smoke, heat, dust, airborne bacteria, carbon dioxide, and replenish oxygen (Wikipedia). According to the, the value of ventilating isn't only related to guests' comfort but also related to the safety and health of whoever stays in the hotel property. However, different rooms and spaces may have different requirements for air ventilation. Guests will feel uncomfortable when there is no ventilation while they are simply sleeping. Kitchens and bathrooms need mechanical exhaust to control odors and sometimes humidity (Handbook, A. 2001). In all public spaces fresh air needs to be ducted from the outside and exhaust air must be removed. Besides fans, a well-designed HVAC system can also ensure effective natural ventilation. The layout of windows, doors and vents must be planned carefully.
As acknowledged by the American Society of Heating, Refrigeration and Air-conditioning Engineers (ASHRAE), ineffective HVAC systems can cause, or help the growth of mold in hotels. 50 percent of all illnesses are caused by polluted indoor air (Freed, 2009). Because of this, mold protection products like air cleanser are worth installing (Martin, 2005). Evaluating HVAC systems regularly and implementing proper operation and maintenance procedures are very important.
HVAC combined with other systems
By using infra-red technology in guestrooms, the HVAC system can be automatically turned on whenever a guest enters an area. The air-conditioning will learn to control the room temperature and the ventilating system will also start to work. If the guest wants to improve the room temperature by him or herself, manual control devices also needs to be accessible. "After the guest leaves the area, the temperature can be adjusted to the particular level pre-set by the hotel to keep energy costs down and provide a more comfortable environment for the guest when he or she returns (Worcester, 1998). " Some similar control systems is often as simple as key card system or as high-tech as a sound-activated system or even biosensors. To find occupancy in the guestroom is now the most effective way to control energy output.
Furthermore, as stated before, by making use of a building automation system, a hotel can control the complete property automatically. Furthermore to regular operations, time scheduling, limiting demand and an early warning system failure can be implemented within an HVAC system (H&MM, 1996). This may significantly help hotels to reduce labor cost, save energy and enhance guest satisfaction.
Another trend is the use of a raised floor with under-floor HVAC system. According to Alwine (2010), an under-floor pathway created by panels can offer a house with something distribution system. Such service distribution systems include modular wiring, passive or active zone cabling and heating and ventilation and air conditioning. Using this system, oxygen can be supplied by air diffusers from below the floor directly into the occupied space. As a traditional overhead service distribution design uses walls and columns to put cables and HVAC systems, an under-floor system can save more space and support more facilities. Furthermore, Alwine (2010) also argued that "raised access flooring affords operators more flexibility to react to equipment layout and technology changes quickly, easily and cost-effectively because updating the interior design does not demand expensive facility investment and construction expenditures. " This is extremely important for hotels because hotels are running 24 hours per day and are cost-sensitivity. This design has been proven very successful in casinos and will also be applied by more and more hotels.
Action Plan
After something design, a hotel must consider some key issues when buying the system (Higgins, 2009). First of all, the performance of the HVAC system needs to be ensured. The hotel must do some research on the business and its products. If possible, they should also try to check the performance of systems in other hotels. Following this, a hotel needs to consider the utility cost and performance cost. Even though some systems may be expensive at purchase, they can save a lot of energy and bring the hotel more benefits in the long-term. The sound level and equipment size are also important considerations. Gloede (2007) argued that a property must determine exactly what heating and cooling load is needed and then spec the system accordingly. Finally, hotels should assess the worthiness of the complete HVAC system to get the the most suitable one for their property.
As an HVAC is a continuous operating system, the hotel cannot disregard it after purchase and installation. A maintenance arrange for the HVAC system must be established to ensure the success of operation. According to Freed (2009), air conditioning comprises 50-70% of a hotel's energy consumption. By properly cleaning the HVAC system, a hotel can save 20-30% on an energy bill. Furthermore, "the number one reason behind heating/cooling system failure is dirt and neglect (Freed, 2009)". Based on these factors, hotels should follow strict maintenance standards and schedules. The advantage of this is that equipment is efficient and less likely to breakdown. The breakdown of an HVAC system not only influences a hotel's revenue, but also results in a health risk.
Hotels can develop a training arrange for employees to allow them to handle the majority of the regular maintenance. On the other hand, hotels also have to outsource experts to do the deep cleaning and preventive maintenance annually. If necessary, large hotels can assign someone to do HVAC energy audits. This person is accountable for operating, maintaining, and controlling the price tag on the HVAC system and reports to the executive engineer. To be able to deal with emergencies, hotels need to develop a crisis response plan. Certain information such as detailed equipment layout drawings and emergency contacts should be prepared to save time and money (Doring, 2000).
Cost Analysis
By upgrading a hotel's HVAC system, employees' productivity can be increased because of an improved working environment (Gann, 1998). According to 1992 Means Construction Data, the installed cost of the HVAC system is approximately 10 percent of the total building construction cost. According to the, a 50, 000-square-foot building needs about $200, 000 to upgrade its system in 1995 (Gann, 1998). If we assume this percentage stays the same and calculate inflation, the total amount will be larger today. This seems to be an enormous expense if a hotel wants to retrofit its HVAC system. The hotel management must also decide whether it's worthwhile, considering the impact on earnings through the renovation period. Based on Gann's calculation, the profits on return will be around 71% and simple payback will be 17 months (predicated on the statistics in 1995 for a 50, 000-square-foot building). Using the development of technology, HVAC systems have become more and more affordable and efficient. Now, as part of your, a new HVAC system will probably be worth retrofitting in a hotel.
The renovation of Marriott Mission Valley's HVAC system saved the hotel more than 700, 000 kWh per year (Fypower). Another research study done by Mode: Green showed that a hotel in Chicago, which installed new thermostats and controllers, could save approximately 22% of the cooling and heating costs with a return on investment under three years.
Conclusion
In order to plan an effective HVAC system, three major elements should be first defined. In energy conservation, water cooled chillers with higher Coefficient-of-Performance (COP) are preferred. Chillers, pumps and cooling towers should have variable-frequency drives installed. This can help the hotel to save lots of energy and spend less. A central control system such as BAS, is suited to large properties. In water conservation, hotels may use a gray water system, or a purification system to lessen water waste and reuse sewage water. Ventilating systems should be designed to safeguard customers' health. Based on their needs, hotels can make to combine HVAC systems with other control systems to micro control each device in the property. Under-floor HVAC systems have grown to be increasingly more popular.
It is a good technique for the engineering department to cooperate with other departments such as rooms division and the human resources department to guarantee the consistency and success of the HVAC system plan. If the management team decides to renovate the HVAC system, a long-term view should be taken. Saving energy, cutting costs, being environmentally-friendly - they are the "Trinity".
