Design of “DeIcer” – A Proposal
Author: Chia-Chieh Yu (2004-04-06); recommended: Yeh-Liang Hsu (2004-04-28).
The purpose of
this project is to design a hand-held heating device for car drivers to melt
ice in keyholes, frozen doors and windows in winter, by blowing warm air on
them. This device is to be used remotely, and should not have any power cable.
The heat source should last about 10~20min before recharge. A functional
prototype, as well as all necessary design documents, is to be delivered.
The use of the
heating device, which will be called “DeIcer” in this proposal, can be
described in the following event sequence:
DeIcer to aim at the target, the user triggers the DeIcer through a triggering
mechanism. The blower starts to suck in cold air from outside
through the air passage, so that the heat source will have enough
time to turn the cold air into warm air. The warm air is then blown out on the
target. The energy required for the blower and heat source is stored in the energy
storage, and all components are packaged in a packaging case.”
this event sequence, there are 6 components in this product: triggering
mechanism, heat source, energy storage, blower, air passage, and packaging case.
Figure 1 shows the interaction between these 6 components.
Figure 1. Interaction between the components
design needs of the 6 components are listed below:
The heat source
provides heat to heat up the cold air. With the energy storage, the heat source
should last for 10~20 min before recharge.
The blower sucks
cold air from outside and blows warm air on the target. The blower should
provide a constant airflow and enough flow rate.
The type of
energy storage depends on the type of heat source and blower selected. It
should provide enough working energy for 10~20 min before recharge.
The air passage
should be properly designed with the heat source, so that the heat source will
have enough time to turn the cold air into warm air.
mechanism should be easy to use. It simultaneously triggers the heat source and
blower. There should be safety devices built in the triggering mechanism, so
that the heat source will not be triggered improperly.
case should contain the other 5 components mentioned above and hold them in
proper positions. The shape of the packaging case should be easy to be held by
hands in use. There should be heat insulation so that the user will not be
burned by the heat source.
Current Products Review
In this section
we first review 4 existing products to help us generate design concepts for
DeIcer: a hairdryer, a lighter gun, a mini vacuum device, and a squirt gun.
(1) A Hairdryer
studied here is the smallest hairdryer we can find. Figure 2 shows the size of
the hairdryer. Figure 3 shows the heat source of the hairdryer. Heating coils
are wrapped around some burning resistant material and spread along the front
part of the hairdryer. Figure 4 shows the heat insulation material wrapped
around the outside of the heat source to preventfrom burning the user. An
electric fan blows outside air through the heat source directly, as shown in
Figure 2. The size of the hairdryer
Figure 3. Heat source of hairdryer
Figure 4. Heat insulation outside the heat source
Figure 5. Blower of the hairdryer
(2) A Lighter Gun
Figure 6 shows
the size of a lighter gun. Figure 7 shows its triggering mechanism. The gas is
provided by an ordinary cigarette lighter as shown in Figure 7. The right side
of the triggering mechanism is a switch that releases gas from the cigarette
lighter, and the left side of the triggering mechanism is a gas pipe that
connects to the cigarette lighter to transmit gas. Inside the red button of the
triggering mechanism, there is an ignition device, which generates an electric
arc at the tip of the lighter gun. Figure 8 shows a safety switch that prevents
the user to trigger it abnormally. We did a simple experiment and found that an
ordinary cigarette lighter (5ml) can last for about 2400sec in the lighter gun.
Figure 6. The size of lighter-gun
Figure 7. Triggering mechanism of the lighter gun
Figure 8. Safety switch
(3) A Mini Vacuum Device
Figure 9 shows
the size of a mini vacuum device. As shown in Figure 10, an electric fan sucks
airthrough the front hole into thebottom of the mini vacuum device. We did a
simple experiment and found that its air flow rate is about 0.5 L/sec. The
electric fan is driven by two parallel AA batteries and can last for about
Figure 9. The size of mini vacuum machine
Figure 10. Air passage ofthe mini vacuum machine
(4) A Squirt Gun
Figure 11 showed
the air flow (solid lines) and water flow (dashed lines) in a squirt gun.
Figure 12 shows the triggering mechanism of the squirt gun. When the trigger is
released, water under high pressure as injected.
Figure 11. Flow passage of squirt gun
Figure 12. Triggering mechanism of squirt gun
Design Concept of DeIcer
From the review
in the previous section, we can generate the design concept for DeIcer. Figure
13 showed the layout of DeIcer. The design concepts for the 6 components are
Figure 13. DeIcer design layout
Among the 6
components, heat source is the most critical. We decide to use a design similar
to the lighter gun in Figure 6 and 7 as our heat source because it last longer
and the energy storage can be easily replaced with an ordinary cigarette
question is, can DeIcer provide an output temperature of between 60-80 degrees
C in cold (between minus 5-20 degrees C) circumstances?
is the fuel used in cigarette lighters. Its heat of combustion is 2870kJ/mole.
Its molecular weight is 58.12g/mole, and its density is 0.5788g/cc. Therefore,
the total heat of combustion of the 5cc butane in an ordinary cigarette lighter
On the other
hand, if the air flow rate of DeIcer is 0.5L/sec, and last for 30 min., the
total air flow will be 900L. The specific heat for air at 32 is 1.71865, the density of air is 1.164kg/m3. Therefore the
total heat required to heat the 900L (0.9m3) air from -20 to 60 (temperature difference 80) is
Two numbers are
really close and we should use two burners in DeIcer to ensure that there is
enough heat. The temperature of the outlet air can be adjusted by turning on
only one burner or both burners.
The Blower of
DeIcer will be an small electric fan similar to the mini vacuum device shown in
concept of the heat source discussed above is a point heat source. The major
design task here is how to extend the heat source along the air passage. The
air passage has to be carefully designed along with the blower, so that DeIcer
can provide a constant and concentrated air flow.
storage for the heat source will be ordinary cigarette lighters, and the energy
storage for the blower will be batteries. The melting point of butane used in
ordinary cigarette lighters is –138.3, and the boiling point is –0.5. In –5~-20 when the product is used, butane will not be frozen.
However, it would be difficult for butane to vaporize. Propane can also be used
in cigarette. The boiling point for propane is –42.1, but heat of combustion is about 25% lower than that of
mechanism has to control an ignition device, to release gas from the ordinary
cigarette lighter, and turn on the blower switch simultaneously.
case will be made from plastic material, and similar to the hair dryer in
Figure 4, heat insulation material will be wrapped around the outside of the
Personnel, and Budget
prototype and necessary design documents (design documents, drawings, test
results, etc) are to be delivered in 6 months after signing the project
contract. Professor Hsu, Yeh-Liang, doctoral student Yu, Chia-Chieh, and master
student Ma, An-I will work part time on this project for 6 months. Table 1
shows the budget of this project. 80% of the budget should be paid to Yuan Ze
University when signing the project contract. 20% of the budget should be paid
to Yuan Ze University after the project is completed. We will waive the intellectual
rights of any results generated from this project. However, for academic
credits, if a product is patented using the design generated in this project,
we do hope to be listed as inventors.