Characteristics and requirements of air conditioning in clean operation Department
The requirement of temperature and humidity in clean operating room is set by medical activity and comfortable needs of doctors and patients. At the same time, the coincidence zone of indoor temperature and humidity meeting these two requirements is 21-25 C, and the relative humidity is between 30% and 60%. If the temperature is too low, although it is conducive to the control of bacterial reproduction, it will affect the flexibility of the doctor's operation. If the indoor relative humidity is too low, the water loss at the edge of the wound will be accelerated and the suture of the wound will be affected. If the temperature is too high and the relative humidity is too high, not only the highly stressed medical personnel will sweat easily, but also the bacteria will be easy to multiply and the operation will be carried out The risk of infection increases. The requirement of temperature and humidity in clean operation Department is higher than that of air conditioning in summer, which is 60% relative humidity at 26 C with the ward in clinic. Strict temperature and humidity requirements are one of the factors that the operating department requires air conditioning for cooling.
Clean operation Department is usually located in the interior of buildings without external walls and windows. The operation Department arranged in the interior area can prevent the invasion of dirty air. But at the same time, another problem is that the room is not easy to heat, which is like the two sides of a coin, and can not be overcome in each other's exterior. Whether in winter or summer or in the clean operation Department of hospitals in the north and South regions, cooling in the clean operation room is the whole process of operation. However, when the clean operating room is vacant, such as in the morning or during the intermission of the operating room, the operation activity stops and the heat inside disappears. When the outdoor temperature is low in winter, to maintain the operating room temperature, heating is needed. The heating quantity varies according to the hospitals in the north and the south. High airtightness, intensive medical equipment and clothing personnel gathered during the operation are the factors that the operation Department requires cooling during the transitional season when they have fever.
To sum up, because the clean operating Department has strict temperature and humidity requirements throughout the year, and the closed clean operating department can not heat in time and naturally, the need for cold source cooling is continuous throughout the year. At the same time, it leads to a high dependence on air-conditioning in the clean operating department, long cooling operation time, large fluctuation of cooling load, more operating rooms in the operating department, higher operating room level, larger cooling load and greater fluctuation. Therefore, the requirement of air-conditioning cold source for clean operating room is to provide chilled water for air-conditioning at any time stably and reliably. In summer, this requirement is better met. If the operating department in the building is in the building, it can share the air-conditioning cold source of the building. If there is no central air-conditioning cold source in the building, it can set up a separate cold source for the clean operating department. However, when the spring and autumn season even enters winter, the corresponding measures must be taken in order to make the air conditioning system run safely, reliably and economically, and meet the requirements of the operating room.
Key Technologies for Solving Transitional Season Cold and Heat Sources in 02 Clean Operating Department
Clean operation Department is generally part of hospital buildings. In summer, the cooling source of air conditioning is generally shared with water-cooled water chillers in buildings. In summer, air-cooled water chillers are also set up separately for operation Department in areas with low outdoor temperature, such as cold areas.
Transition season usually refers to autumn, early winter and spring, when the temperature is low, but air conditioning is still needed for cooling in the clean operation department. In Beijing, the transition season extends to about - 5 C, that is, when the outdoor temperature is - 5 C, the refrigeratory still needs to be turned on for cooling. In order to meet the requirements of operating room cooling, there are usually three solutions:
The first type: direct opening of water-cooled water chillers used in summer
The key point of adopting this scheme is that the cooling water temperature of the chiller should satisfy the start-up temperature of the chiller and the freeze-proof of of the cooling tower. When water-cooled chillers start-up, there is a minimum water temperature requirement for cooling water. Usually, it is about 15 C. When the outdoor temperature is lower than 5 C, the water temperature and air temperature in cooling water system are basically the same. At this time, the cooling water temperature often does not reach the start-up temperature of chillers, which shows that the chillers start-up but do not operate, in order to meet the requirements. In order to meet the requirement of minimum start-up temperature of cooling water for refrigerators, cooling water heating measures should be set up. Cooling water heating can be solved by individually setting cooling water bypass cycle and plate heat exchanger heating cycle. At the same time, cooling towers need to set up anti-freezing measures. This system has the lowest investment, simple operation, convenient and reliable, but it can not fully use outdoor cold source and has poor energy-saving effect.
The second type: cooling tower + plate heat exchanger system
The key point of this scheme is to prevent the cooling tower from freezing. In winter, the water-cooled chillers stop running. The natural heat dissipation of the cooling tower is used as the cooling source of air conditioning. The cooling water of the cooling tower passes through the exchanger to produce chilled water for air conditioning. For the north, when the outdoor temperature is very low in winter, the cooling water needs to go up to the tower to dissipate heat, and electric tracing is needed to prevent the cooling tower from freezing. The operation of this system is complex, which requires higher operation skills, longer operation time and higher investment.
Third: Air-cooled water chiller system with natural cooling
The key point of this scheme is to set up a natural cooling air-cooled water chiller for the operation Department alone, and to switch with the air-conditioning cold source system for the operation Department in summer. The difference between natural cooling air-cooled water chiller and general air-cooled water chiller is that the unit can automatically identify whether to open the refrigeration compressor in the unit. When the outdoor temperature is low, if the natural heat dissipation can meet the water temperature requirements, the refrigeration compressor stops working, only when the natural cooling can not meet the requirements, it needs to open. Because the chiller set up for the operation Department alone needs to be switched with the cooling water system used in summer. According to the different systems, the switching places are not the same, and a set of water system devices such as water supply and constant pressure need to be separately, so that the switching can be completed before normal operation. This system is relatively simple to operate and has good energy-saving effect, but it has a high investment.
Suggestions on option selection of 03
There are many factors to be considered in determining the cold source in the transition season of the clean operating department. The first factor must be safe and reliable. If there is no cooling measures in the operating room, the temperature of circulating one hour will increase by about 2-3 degrees C, and the temperature will rise to 30 degrees C in about two hours, which is very dangerous. The second factor is the operation of air conditioning in hospital logistics. Experiments show that the intellectualization of cold source system can make up for the lack of operation experience, but the degree of intellectualization of automatic control and automatic regulation varies greatly from hospital to hospital according to the design of automatic control and the level of funds. When the degree of intellectualization is low, the work of manual operation is required to be high, and it takes a long time to accumulate experience to operate safely. Energy-saving system, long cooling time and high intensity of clean operation department, large refrigeration power consumption, high operating costs, energy-saving system is very helpful to reduce hospital costs.
In a word, to determine the cold source in the transitional season of the operating department, we need to evaluate the factors such as the location and climatic conditions of the hospital, the local energy policy and the supply conditions of energy, the requirements of hospital management, the experience and operation habits of hospital operators, the management requirements of the operating department and the number of operating rooms in an all-round way to determine the best one. Individualized solutions suitable for hospital requirements.