Application：Combined AC, fresh air unit, fan coil, blast pipe

Features：

　　Save on distance in humidifying segment in the AC
Abolish or replace dash plate
Clean
Safe, reliable, long life
Silent
Standard automatic control interface

Working principle：

　　●Working principle of wet-film vertical drainage：

Schematic diagram of wet-film vertical drainage humidifier

　　Clean tap water via solenoid valve is fed into water distributor on the top of wet-film so as to humidify the surface of wet-film. Water flowing into water-containing tray will be drained into sewer pipe through drainpipe elbow, which does not reuse the water. When hot air passing through humid wet-film, the humidity is increased and temperature drops. This humidifying process is called isentropic humidifying process. (Note: if water temperature is lower than that of dew point, it is called enthalpy drop process.) Part of water in wet-film will be boiled, but no additional energy is expended in this process.

　　●Working principle of wet-film circulating water：

　　Clean tap water or refrigerating water is fed into wet-film’s circulating tank via intake pipe. Water in circulating tank is controlled by float valve or liquid level switch, pumped by the pump into water distributor on the top of wet-film and distributed evenly, which will fall down along with the surface of wet-film by gravity and humidify the surface of wet-film. When air is put through humid wet-film, the humidity will be increased and temperature drop. This humidifying process is called isentropic humidifying process. (Note: if water temperature is lower than that of dew point, it is called enthalpy drop process.) Part of water in wet-film will be boiled, but no additional energy is expended in this process. Unevaporated water dropping from wet-film flows into circulating tank and is pumped onto the top of wet-film by pump. Above-mentioned process will circulate repeatedly so as to save water.

Working Conditions：

　　Environment temperature & humidity: wet-film: 1~100℃; electric cabinet: 0-40℃1~50℃，90%rh
Critical air velocity: <4.0m/s
Feed water quality: Tap water or the like
Water pressure: 5~40℃
Water pressure: 0.15~0.75Mpa

Overall schematic diagram：

　　●Vertical drainage

 　●Circulating water

 

Model description：

Technical Parameter Table：

●Wet-film dash plate(SMDS)

Model	Thickness of Wet-film (mm)	Proportion	Slope angle	Extreme air speed (m/s)	Standard resistance (mmH2O)	Water content(g/kg)
SMDS-50	50	1:44	45°	3.8m/s	2	0.2
SMDS-100	100	1:44	45°	4.5m/s	3.8	0.1

●Wet-film humidifier(SMPA)

Model	SMPA-50	SMPA-100	SMPA-150	SMPA-200	SMPA-250	SMPA-300
Thickness of Wet Film(mm)	50	100	150	200	250	300
Humidification ratio(%)	30	55	70	80	85	90
Air resistance(Pa)	20	35	50	75	85	93
Humidifying effect	Testing condition: in intake air condition: dry bulb temperature: 40℃; relative humidity: 15%RH;air speed: 2.5m/s; water temperature: 20℃
1m2 standard humidifying capacity(kg/h)	23	44	56	64	68	72

●Wet-film humidifier(SMPB)

Model	SMPB-50	SMPB-100	SMPB-150	SMPB-200
Thickness of Wet Film(mm)	50	100	150	200
Humidification ratio(%)	40	68	82	88
Air resistance(Pa)	30	50	80	90
Humidifying effect	Testing condition: in intake air condition: dry bulb temperature: 40℃; relative humidity: 15%RH; air speed: 2.5m/s; water temperature: 20℃
1m2 standard humidifying capacity(kg/h)	34	56	68	72

●Organic germproof wet-film humidifier(SNPC)

Model	SNPC-50	SNPC-100	SNPC-150	SNPC-200
Thickness of wet-film(mm)	50	100	150	200
Humidification ratio(%)	30	55	84	90
Air resistance(Pa)	20	38	53	78
Humidifying effect	Testing condition: in intake air condition: dry bulb temperature: 40℃; relative humidity: 15%RH;air speed: 2.5m/s;water temperature: 20℃
1m2standard humidifying capacity(kg/h)	36	58	70	74

Wet-film’s Air Resistance Calculation at Different Air Speed：

　　If the standard air resistance of some wet-film is P0,
(Note: standard air resistance refers to the resistance at 2.5m/s)
And the real air speed in AC via wet film is V,
Then wet-film air resistance P=P0×(V/2.5)2

Working Conditions of Wet-film：

　　(1) Environment temperature & humidity: wet-film: 1~100℃; electric cabinet: below 1～50℃ 90%RH

　　(2) Critical air velocity: <4.0m/s

　　(3) Feed water quality: Tap water or the like

　　(4) Water pressure：5～40℃

　　(5) Water pressure：0.15～0.75Mpa

The Variation of Wet-film Humidifying Capacity at Different Air Conditions:

　　Wet-film standard humidifying capacity refers to the wet-film humidifying capacity when the drenching one is larger than the minimum working draining water content in following intake air condition: dry bulb temperature: 40℃;relative humidity: 15%RH; air speed: 2.5m/s; water temperature: 20℃. As environment conditions change, wet-film’s humidifying capacity will change. Here are the variations of humidifying capacity while intake air temperature changes

Selection Examples:

　　For example, total ventilation of the AC in some electric plant is 30000m3/h and that of fresh air ratio is 30%, outdoor temperature and humidity in winter are -4℃ and 70%RH respectively.

　　It is required to make indoor temperature reach 22℃, 50%RH. 　Question: which model of wet-film circulating water humidifying & cooling down system is suitable?

　　(1) Calculate efficient humidifying capacity required by AC:

　　　　Water content of outdoor air in winter is 2g/kg; water content of air in plant is 8.2g/kg

　　　　So W=1.2×[30000×30%]×[8.2-2]×10-3×1.2（safety coefficient）=80kg/h

　　(2) Correction coefficient of wet-film:

　　　　If wet-film’s intake temperature is 25℃ and relative humidity is 32%RH, you can find the coefficient from the wet-film Temperature & Humidity Coefficients: N1=0.53

　　(3) The selection of wet-film thickness:

　　　　Calculate wet-film’s standard humidifying capacity（kg/h）

　　　　Suppose wet-film area =AC heat exchanger area =3.4m2

　　　　Wet-film’s airward speed=30000m3/h÷3.4m2=8823m/h=2.45m/s

　　　　Wet-film’s standard humidifying capacity/m2 = (valid humidifying capacity÷ Temperature & Humidity Coefficients)÷ (air speed via wet-film ÷2.5) ÷ wet-film area

　　　　　　　　　　=（80÷0.53）÷（2.45÷2.5）÷wet-film area

　　　　　　　　　　=154÷wet-film area=154÷3.4=45.3kg/h/m2

　　　　If choosing SMPA wet-film: SMPA（XH）- (wet-film mainframe: width × height)-150 wet-film circulating water humidifier

　　　　If choosing SMPB wet-film: SMPB（XH）- (wet-film mainframe: width × height)-100 wet-film circulating water humidifier

　　　　Generally, SNPC wet-film is used for vertical drainage.

　　(4)If AC ventilation is 30000m3/h, the length of water tank L1=150+200=350mm; height H1=250mm;
if the AC is left type, namely the outlets of surface cooler and heat exchanger are placed on the left of AC (along air direction)

　　　　If choosing SMPA wet-film: SMPA（XH）-150-350×250-L wet-film circulating water humidifier

　　　　If choosing SMPB wet-film: SMPB（XH）-100-350×250-L wet-film circulating water humidifier

Recommended：

　　Obviously, the greatest strength of wet-film circulating water humidifying method is water and energy conservation that is in accordance with the request of water saving in China. Water scales and bacteria will be produced due to long-term use, so they should be resolved through effective measures!

　　［Solutions］※ Add fresh water unceasingly, utilizing its hypochlorous acid to sterilize and keep germ out

　　　　　　　　　※ Prevent the enhancement of salt concentration in water by forced drainage to reach anti-scale purpose

　　［New STAND anti-scale germproof technology］

　　Therefore, wet-film circulating water is a good humidifying method. If we prevent the formation of bacteria and water scales, we can work more efficiently. Following mature technologies are used according to the features that water hardness is too high.

　　Conclusion: It is suggested that new electric cabinet (model: JWMK-X) which can prevent scales and bacteria is suitable for high sanitary condition places to ensure good sanitary performance and reliability of system.

　　Countermeasure: To use new germproof anti-scale wet-film circulating control mode

STAND single-chip intelligent germproof scale-proof electric control system 　　Use: Prevent performance reduction after wet-film forming scale； 　　　　　Protect wet-film from legionella； 　　　　　Improve humidifying sanitary state

STAND single-chip intelligent germproof scale-proof electric cabinet

Description of wet-film cooling down：

——Working principle of wet-film cooling down

　　Wet-film cooling down is isenthalpic cooling down, which realizes cooling down by water absorbing large quantity heat as it vaporizes. Vaporization of 1 Kg water can absorb about heat of 586 kcal., so in hot summer, the air conditioner cools the environment by the evaporative cooling of wet-film. Compared with the traditional refrigerating unit cooling down, wet-film cooling down is featured by low investment and low energy consumption in operation. Therefore, it is applicable to the general cooling-down in workshop, storehouse, and the public places.

——Applicable areas of wet-film cooling down

　　It is applicable to the northern regions in summer, cooling down up to 8-11℃; for the southern regions, it also has favorable effects, cooling down about 3-5℃. Besides, what should be emphasized is that wet-film cooling down system should use fresh air handling system and the fresh air amount of air conditioner should be over 10 times more than the interior space.

——Systemic configuration of wet-film cooling down

　　Generally, the wet-film cooling down system is composed of blower, air unit, cooling down wet-film for evaporative cooling (generally 250-300mm thick), circulating water tank, circulating water pump, and control box. The system is simple, without refrigerating unit or cooling tower. It consumes energy only several KW (Note: it excludes energy consumption of blower.)

——Why does not suggest using vertical drainage in wet-film cooling-down in summer:

　　The working principle of wet-film cooling down in summer：
a·Water vaporizes and absorbs large quantity heat in the air.
b·水与热空气的接触交换吸收空气的热能

　　Both of them demands sufficient contact between water and air, that is, large quantity water leaches from the wet-film, so as to ensure the cooling down effect. However, vertical drainage may consume so much water due to large quantity leaching water and the users cannot bear it; if the leaching water is little, the real cooling down effect will not be realized; the circulating water mode has no such trouble. You just need to install a set of anti-microbial scale-inhibiting circulating water control system.

Technical parameter table：

Wet-film humidifierSMPA	Wet-film model	SMPA-200	SMPA-250	SMPA-300
	Wet-film thickness (mm)	200	250	300
	Humidification efficiency (％)	75	83	90
	Standard air resistance (Pa)	75	75	93
	Rated humidifying capacity (Kcal)	31500	34860	37800

Note: (1) The standard air resistance in the table indicates the resistance of wet-film under conditions of 2.5m/s wind speed.
(2) The rated humidifying capacity indicates the humidifying capacity supplied by water vaporization in such condition of air passing through wet-film: t dry bulb=38℃, t wet bulb=30℃, surface wind speed 2.5m/s, and ventilation 10,000m3/h.

Model selection：

[Example] Coating air conditioner of some automobile coating workshop is fresh air supplying mode, with ventilation of 160,000m3/h. Under the hottest condition in summer, it is 38℃ and 40%RH. Now the interior coating technique demands relative humidity of 75%RH and the low temperature is better. However, the traditional refrigerating unit costs much in operation and investment, the user cannot afford it. So they realize cooling down of coating workshop by wet-film isoenthalpic cooling mode.

　　According to the enthalpy-humidity chart, we know that wet-film isoenthalpic cooling mode makes the interior supply air 29.5℃ and 75%RH, requiring wet-film humidification efficiency of 73%. From the chart, we also know that the wet-film thickness is 200mm. Considering certain safety factor, we recommend to use 250mm thickened wet-film. And the air conditioning supplies air in 29.5℃. Coating air conditioner is fresh air conditioning system, with large ventilation and ventilating times up to 20, and there is not large heating equipment in doors and the external heat load is not large, so interior air temperature of coating workshop can be generally controlled in 30℃ and the humidity meets the technical demands of coating technique 70%RH.

Direction for use：

　　▲ Adopting wet-film isenthalpic cooling down mode realizes favorable effect in north regions in summer and many fields in southern regions, such as gymnasium, chemical plant, machining plant, leather factory, recreation ground, waiting room, shopping mall, coating factory, amusement park, and storehouse, etc.

　　▲ Adopting wet-film isenthalpic cooling down mode must use fresh-air air-conditioner air supply. Otherwise, the cooling down effect should be influenced.

　　▲ As adopting wet-film isenthalpic cooling down mode, large air supply amount may realize large cooling down effect. Generally, the air supply amount should be over 10 times larger than the cooling down space