Hotel Facilities Management: Cooling Systems and Ventilation Systems
1. a) Refrigerant is the source of heat. Water at (1) is pumped out of the condenser, where it was used to cool the refrigerant. Water absorbed the heat from the refrigerant, and its temperature increased.
b) At (2), the heat of the water is absorbed by the refrigerant in the pipe, which temperature increases, and the water temperature decreases.
c) The component at (3) is called an evaporator. The purpose of the evaporator is evaporation of the refrigerant, when it absorbs heat from the warm water. As a result, water leaves the evaporator with lower temperature.
d) The component at (4) is called a condenser. The purpose of the condenser is condensation of the compressed gas into liquid.
e) At (3), the refrigerant is low temperature and low-pressure gas.
f) At (4), the refrigerant is a warm temperature and high-pressure liquid.
g) The device (4) would serve as an evaporator.
h) The water at (5) is moisture from the wet air that is removed from the room.
i) Heat from the room is transferred to cold water that goes to the evaporator.
j) Yes. The system uses Freon as a refrigerant.
k) The water at (6) is cooler than the water at (7). Water (6) absorbs the heat from the refrigerant and its temperature raises.
2. a) The cold food is being held at -50%u02DAF, which is equal to -45.5%u02DAC.
b) According to the diagram, the condenser is cooled by air.
c) At (9) the refrigerant is a warm temperature and high-pressure liquid.
d) The system best resembles the split system as it has indoor and outdoor units that operate together while PTAC has both combined in one frame.
e) The component at (10) is an evaporator. It is removing heat from the refrigerant.
3. The common practice of ozonizers use in hotel rooms is an ineffectual mean for indoor air pollution control. The manufacturers of ozonizers claim that the devices clean air by oxidizing the harmful organic compounds and induce dust and pollen sedimentation.
The EPA report claims that ozone reacts very slowly with the compounds that are typically present in the rooms, for instance, carbon monoxide or formaldehyde. Some organic substances react readily with ozone (as those emitted by the new carpets), but the reaction produces other compounds, making total concentration of organic substances higher after the interaction.
Ozone is not a component of the air. Although some vendors advertise ozone as “pure air” or “energyzed oxygen”, it is a toxic gas. Even low concentrations of ozone can cause various respiratory disorders, as throat irritation coughing, shortness of breath, etc. Ozone exposure can also cause worsening the chronic respiratory diseases (asthma).
Since ozonizers do not control indoor air pollution and produce a toxic gas, their use in public places should be ceased. No federal government agency recommends ozonizers use. EPA states, they can cause health problems at high concentrations.