Temperature Sensitive Material for the Desiccant Dehumidification

System

Jun HUANG, Yan XU and Kenneth HUANG

1085 heping Road, Shenzhen, 518010, China

EPEE2016/MCSSE2016/AMST2016/ETMI2016

Agenda

1. Introduction

2. Polymerization of NIPAAm with Silica Gel for Dessicant

3. Preparation of Temperature Sensitive Hydrogel with Silica Gel at Different Ratio

4. Differential Thermal Analysis

5. Conclusion

1. Introduction

To minimize the energy consumption of an air-conditioning sub-system, temperature sensitive poly N-isopropylacrylamide hydrogel with temperature non-sensitive porous silicon gel was made through solution polymerization. The polymer yield, water absorption, and the water discharge rate were observed using a differential thermal graph. This graph provided the details of the temperature response of water molecules. These gels were placed on glass paper soaked with acid for dehumidification system. The critical temperatures for the synthesized polymer has lower critical solution temperatures, we reduced the cost and improved performance by using the optimized synthesizing ratio.

Carl Georg Munters (March 22, 1897 – 1989) was a Swedish inventor, most known for inventing together with Baltzar von Platen the gas absorption refrigerator and foamed plastic now styrofoam.

1. Current solution in USA

1. Solutions from Europe

lithium chloride

1. The semiconductor solution

1. Solution from China

Rotor

Molecular sieveceramic rotary

2. Polymerization of NIPAAm with Silica Gel for Dessicant

1 gram NIPAAm is required to add a the initiator 0.0203g Bis and crosslinking agent 0.0136g AIBN.

mSiO₂·nH₂O

2. The solution polymerization

shake it every half hour until it jelly shape, after 24 hours rinse with deionized water every 8 hours for 4 consecutive days

2. Glass paper soaked with acid

3. Preparation of Temperature Sensitive Hydrogel with Silica Gel at Different Ratio

The molecular structure of this kind of gel has an equilibrium region, hydrophilic region and hydrophobic region with their common characteristic as the Low Critical Solution Temperature (LCST). Under the critical temperature, the polymer chain and water react with water molecules and the gel swells, leading to storage of surface energy.

Above the critical temperature, the gravitational attraction between the hydrophobic groups in the polymer chain is enhanced and the hydrogen bond between the hydrophilic group and the water becomes weak, resulting in the gel shrinking in size and surface energy to release.

3. Material ratio and yield

4. Differential Thermal Analysis

A DTA consists of a sample holder, thermocouples, sample containers and a ceramic or metallic block; a furnace; a temperature programmer; and a recording system. The key feature is the existence of two thermocouples connected to a voltmeter. One thermocouple is placed in an inert material such as Al2O3, while the other is placed in a sample of the material under study. As the temperature is increased, there will be a brief deflection of the voltmeter if the sample is undergoing a phase transition.

4. Pure silica gel

4. Pure hydro gel

4. One third silica gel

4. One third hydro gel

5. Conclusion

By coating or synthesizing the temperature sensitive material onto a dehumidifier runner, the traditional dehumidification system with activated silica gel can be improved.

the function of the hydrophobic molecules is due to the change in the cross linking network of hydrophobic and hydrophilic balance caused by temperature.

hydrophilic groups with water inside the molecule interacting between molecules when the temperature is lower than the critical temperature, the interaction between the molecular chains of water molecules and the poly N-PNIPAAm is mainly amide group and hydrogen bonding.

we are seeking to find new technology for polymerization that is faster than the current one or making the process corrosion resistant to manufacture on glass paper.

Acknowledge

This research was financially supported by the SeaEco Desorbing Technology Division

and Nanjing Kanal Ltd. Ms. Yunxia Ji, Ms. Xiaxia Xu, and Mr.

Peitong Li have contributed plenty of their lab times.

Thanks go to Mr. Liang of Ecotech Rotor for valuable feedbacks.

Thank You !

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