For new buildings, you can specify an air of greater capacity to condition the additional outside a

The update of the standard ventilation requires 15-20 PCM outdoor duke blue devil basketball air per person duke blue devil basketball for most general applications. This represents an increase of 4-5 times over the requirements of the previous standard, which was 5 PCM. A proposal to implement the new standard in existing buildings is to modify the air handler, so that the introduction of outside air increases.
For new buildings, you can specify an air of greater capacity to condition the additional outside air into the hot and humid months. For air handler in use, the original design possibly reflected the need to handle the sensible and latent space conditioning load, and just 5 PCM outdoor air per person.
For new buildings, even with additional cooling capacity, the handler may be inadequate to deal with the heat and humidity. In general, some dry bulb temperature duke blue devil basketball of the outgoing air program, but in this case an excess of moisture in the air, the design increases because the handler can not remove additional latent load during left rainstorm. duke blue devil basketball
A pretreatment solution air handler in new buildings, the requirements duke blue devil basketball of the standard, duke blue devil basketball can be used in a pretreatment system duke blue devil basketball to remove moisture dehumidification duke blue devil basketball and heat, before introducing duke blue devil basketball outside air to the existing handler (see Figure 1 ).
A pretreatment system should emulate the typical return air conditions, which are 72 C and a relative humidity of between 50 and 60%. A standard full dehumidification system overheating can remove moisture, but will cause problems because normal outlet air temperature can rise to 95 F. A standard air conditioner can not remove moisture enough to solve the problem. What is required is a dehumidifier capable of partial overheating, ensure that the outgoing air has a relative humidity of 50% and is not too hot. In fact, not only reach the dehumidifier 50% relative humidity, also have a capacity of partial overheating, so that the air passing the handler have consistent design conditions duke blue devil basketball of room temperature.
Direct supply space In some applications, it is desirable to directly input specific rooms with outside duke blue devil basketball air, instead of using the indirect method. The solution is similar, except that the outside air treated by the dehumidifier partial heat directly enters the building. When direct supply of outside air into the space is used, it is important to specify that the air temperature must be controlled in relation to a specific value in all operating modes: full, partial and winter load. In this case, it is useful variable dehumidifier to achieve partial heating temperature control.
F BTU / lb F BTU / lb F BTU / lb 35 12.9 52 21.4 69 33.2 36 13.4 53 22 70 34 37 13.8 54 22.6 71 34.9 38 14.3 55 23.2 72 35.8 39 14.7 56 23.8 73 36.7 40 15.2 57 24.5 74 37.6 41 15.7 58 25.1 75 38.5 42 16.1 59 25.8 76 39.5 43 16.6 60 26.4 77 40.5 44 17.1 61 27.1 78 41.5 45 17.6 62 27.8 79 42.5 46 18.1 63 28.5 80 43.6 47 18.7 64 29.3 81 44.6 48 19.2 65 30 82 45.7 49 19.7 66 30.8 83 46.9 50 20.3 67 31.6 84 48.1 51 20.8 68 32.4 85 49.3 Table 1. Values of enthalpy (BTU / lb) at various temperatures condensed point ( F) RH => 99.90%
Calculations for the removal of energy The air entering the dehumidification system is 100% outside; System the appropriate size is selected by calculating the amount of energy that must be removed from the air entering the maximum design condition for a point of outgoing air condensate.
The direct calculation method is called enthalpy (or latent heat) Total. It is based on the difference duke blue devil basketball of enthalpy (Btu / lb) between the maximum design condition and the specified condition of the exhaust air, multiplied by the airflow. Amount of heat (BTU / hr) = Difference in enthalpy (h / BTU / lb) x Airflow (PCM) x 4.5 (min / hx lb / ft 3 / min).
For example, to determine duke blue devil basketball the size of a dehumidifier pretreatment to enter a building requiring 2000 / ft 3 / minute bath, Table 1 shows a value associated enthalpy of 41.5 BTU / lb (78 F wet bulb = 78 F point condensate). If the expected air handler 72 F and 55% relative humidity, condensate or a point 55, to search for a corresponding enthalpy in Table 1 of 23.2 BTU / lb. The dehumidifier need enough capacity to remove power: required duke blue devil basketball proportion of energy removal (BTU / hr) = (41.5 - 23.2) x 2000 x 4.5 = 164.700 BTU / h.
The method simplifies duke blue devil basketball the total enthalpy determination