Ultra Power-Saving Passive Cooling Dehumidification System

1-1. Technology Outline



Passive cooling system is the medium to transfer heat organically by using the difference of gravity and density of natural energy (cold and warm heat), and it is the technology to embody no-power or low-power air-conditioning system by using phase change material. This technology not only saves the cost of air-conditioning by reducing the amount of used energy significantly but also protects environment. Passive cooling system is expanding from living goods to communication, power-plant, military and so forth, and it is used more broadly in the advanced countries such as Italy, Germany, United States and so forth where environmental protection and energy-saving is a part of living.

1-2. PCM



As the material that absorb or emit heat by changing phase from solid matter to liquid and gas or from gas to liquid and solid matter at a certain temperature, PCM is the compound material by controlling the characteristics of material such as phase change temperature, latent heat and so forth as chemical change is given to a material with excellent latent heat and thermal storage performance. It is the material that has a higher latent heat capacity compared to water. Its phase change process is shown in the picture below.  

W = Thermal Energy Generated from the Equipment
C = Thermal Medium that Stores Internal Heat 
R = Heat Resistance (Insulation)
T = Heat Exchanger that Emits Internal heat to Outside

Day : <Fig. 2>   When the external temperature is higher than internal shelter temperature,

        it absorb and store energy W simultaneously.

        (PCM changes from solid matter to liquid)
        T does not operate. It prevents the increase of internal temperature.
Night :<Fig. 3>   When the external temperature is lower  than internal shelter temperature,

          It absorb energy W and emit as T simultaneously, T emits accumulated energy
          received from C during the day. C returns to the initial state
         (From liquid to solid matter)

1-3. Characteristic of Passive Cooling System

ⓐ With the performance improvement of PCM and commercialization technology, heat exchange is possible

    by natural convection method (no power).
ⓑ Design by injecting distilled water, PCM and so forth to vacuumed PCM Cell at a desired

    temperature, design and manufacture are possible according to the diverse system requirements

    of the customer (multiple kinds small quantity production is possible)
ⓒ Absorption heat energy amount: 50W power consumption replacement effect for 1g

    of refrigerant 

Igloo magazine dew condensation phenomenon causes increase of ammunition badness rate due to erosion and mold on ammunition, decline of combat ability due to the increase of shell badness rate, increase of operation badness rate of equipment such as tank (instant response is impossible) and excessive use of manpower and cost for replacement work. There is ultra power-saving passive cooling system that can solve such problems.
Generally, the indoor temperature of domestic igloo magazine storage during summer is 23~33℃ with 70~92% of relative humidity, and dew condensation can occur in the middle and lower part of the wall. Therefore, technology is needed to prevent this.  

Relative humidity must always be maintained at 50~60% (average 55%) in order to prevent dew condensation and erosion on ammunition, and this must be solved not by evaporation but by dehumidification. In addition, to magazine, dry dehumidification method is more appropriate than wet dehumidification method, and system must be manufactured by observing NATO's ammunition manual (AASTP-1).   

2-1. System Principle

Ultra power-saving passive cooling system is designed to suck in the cool and humid air inside the magazine through the dew condensation prevention system (dry dehumidification system) installed outside the magazine and make it into dry air before re-supplying it into the magazine so that the moisture in the air is reduced and proper humidity is maintained. On the other hand, through sealed outdoor rack is hot because of the heat generation of the dry dehumidification unit itself and the solar radiation, it has the function of passive cooling system to maintain a proper temperature (20~35℃) to prevent system malfunction through heat exchange with outside air so that dehumidifier and controlling system can operate stably and effectively along with remote surveillance controlling function. 
For the rack, IP54 (water-proof, moisture-proof) standard is applied. It is the international standard protection grade satisfying IEC (International Electro-technical Commission)'s EN60529/IEC 529, which is the same as the standard of NEMA (National Electrical Manufacturers Association). For the internal equipment, machinery management regulation 98/37/EEC appropriate for Europe CE approval, low voltage management regulation 73/23/EEC (fixed version of 93/68/EEC), EMC management regulation 89/336/EEC (fixed version of 92/31/EEC and 93/68/EEC) are applied.  

2-2. System Concept

ⓐ Passive cooling system, that does not use fan, heat exchanger,  air-conditioner and so forth to prevent the dew condensation inside 

    the outdoor rack and cool the  heat source inside the rack but  maintains a certain temperature with 100% no power, is  applied.
ⓑ Dehumidification unit sucks in the air inside the magazine, absorbs the moisture into the dehumidification rotor and emits it in reproduction part.
    It has by-pass controller and operates when necessary.

3-1. System Structure and Characteristic

3-2. Dry Dehumidification Technology

ⓐ Necessity
- Observe NATO's ammunition manual (AASTP‐1)
- In the magazine, dry dehumidification method is more appropriate than wet dehumidification
Method

 
ⓑ Technology Outline
- As the dry dehumidification method that absorbs and removes moisture in the air at the honeycomb-type silica gel rotor, it useless energy than anti-heat anti-moisture device (wet dehumidification system) by moving to enthalpy line. It is excellent in dehumidification effect (can reach the relative humidity of less than 1%).
 
ⓒ Dehumidification Unit Cycle
- Dry dehumidification unit is the method to perform excellent dehumidification function by cylinder type rotor. Rotor is durable and semi-permanent with ceramic honeycomb structure. Silica gel is coated inside, and it has the dehumidification capacity to make outside air of 100% relative humidity into the air less than 30% relative humidity easily

- Divided into process part and reproduction part, this rotor rotates with a low speed (9~18RPM), and processed air and reproduced air flow through each part to the opposite direction and performs dehumidification. The humid outside air becomes dried as it passes through the process part of the rotor and is induced inside. The process part's rotor surface that absorbed lots of moisture is induced into the reproduction part by rotation. 

- In the reproduction part, by using steam or electricity as the heat source, reproduction air is heated
to the temperature of 120℃~140℃ and passed through the rotor. By this hot air, the wet rotor
surface of reproduction part coming from the process part becomes dry and returns to the process
part. In this way, as the rotor  performs dehumidification and reproduction continually, it can perform excellent dehumidification function under any circumstances. 

3-3. Remote Monitoing

When there are many facilities to manage, reduce cost and improve effectiveness through remote
monitoring

ⓐ Function and Characteristic
Along with the dehumidification device that controls the  temperature and humidity of ammunition storages scattered in various areas, it monitors the temperature and humidity inside each ammunition storage, temperature and humidity of outside air, temperature and humidity inside dehumidification device, operation state and alarm signal of dehumidification device and power consumption amount of dehumidification device and provides environment to control the dehumidifier remotely.

.

ⓑ NATO's Ammunition Manual (AASTP 1)
- Section III 2.6.3.4. Ventilation of Magazines
Humidity inside magazine must not rise excessively, and relative humidity must be maintained at 50%~60% for maximum ammunition durability. Humidity higher than this range can cause rapid aging of the stored ammunition, and low humidity can rise the problem of static electricity of the ammunition raw material.
※ Observe NATO's ammunition manual (AASTP-1): Temperature control and record 

- Section III 2.6.3.5. Temperature (temperature)
a) Temperature control is very important to the magazine that is affected by extreme temperature.
b) Magazine temperature record must be maintained in the following cases.
c) Internal temperature of normal ammunition must be maintained at 5~25℃.
However, 10~15℃must be maintained for the maximum ammunition durability.

Generally, higher temperature cause leaking of explosive content, crack or increased consumption of chemical stabilizer. Lower temperature can cause leaking of nitroglycerine or freezing or can change the physical nature of the gunpowder.
 

As New Technology Upbringing Project (TBI) governed by the Ministry of Commerce, Industry and
Energy, it was installed at the third magazine (5291 base) in 2007 and is being operated smoothly.
ⓐ System can be installed without large scale change or damage to the existing magazine.
ⓑ System can be installed in the minimum amount of time by using explosion-proof, sound-proof, water-proof technologies  and materials that have been approved domestically and internationally
ⓒ There is no problem of entrance and exit and equipment operation due to the installed system
during ammunition management, loading and unloading
ⓓ Low energy consumption compared to the excellent dehumidification capacity and no
environmental problem

ⓔ Smooth military operation is possible when necessary because of the dew condensation
prevention capacity on ammunition and shell Magazine storing environment improvement
(equal temperature distribution and maintenance of appropriate relative humidity) 

6-1. Expected effect when installed at magazine

ⓐ Saving of military budget
    - Save annual maintenance cost for magazine dew condensation
    - Save maintenance cost
ⓑ Create excellent storing environment of the magazine

6-2. Effect to Military Industry Field

ⓐ Create excellent underground environment when applied to underground bunker and similar facilities - Construction is possible without concrete change when repair work is performed in order to improve storing environment of underground storing facility.
 It has excellent constructability, economy efficiency and maintenance efficiency compared to other methods.
ⓑ Expand to new military industry field
- Movable shelter installed at truck Install control center to control modern weaponry in the field, fire control center, storage, movable field hospital and so forth to movable truck by using aluminum rack or shelter.
- Ship is operated in humid condition, and serious problems can occur to the sensor, weapon and control system and propulsion system due to high salinity and humidity. Traditional heating method can only reduce the effect of moisture but can not remove it, and it can not be used in summer and inefficient in cost.
- Use on the ground: armored vehicle, vehicle, spare part, ammunition and so forth that are stored for long time.
- Use in airplane hanger :
 As modern fighter planes are sensitive to moisture, planes are sensitive to regular deployment,
long waiting time on the ground and so forth. Turbine erosion is connected to safety and needs special attention, and it is affected by erosion while it is on the ground. 

“PES” Co., Ltd. moved into Incheon Defense Venture Center in July of 2005. With the support of defense venture operation center and as the policy task of New Technology Upbringing Project by the Ministry of Commerce, Industry and Energy, it developed dehumidification system and commercialized it. Patent application is in progress for igloo magazine dehumidification system.
Igloo magazine dehumidification system connected to the company's passive cooling system is considered to have significant effect not only on defense field but also on civilian field.
In the age when oil price is high and nature is being damaged, the company plans to consider nature and humans and develop highly advanced energy-saving technology with passive cooling technology.