Fridgeyser
Fridgeyser
Here is one such arrangement for energy saving.
Following
house hold gadgets are common in almost all homes.
Domestic Refrigerator ……….. colloquially Fridge.
Hot water system ………………. colloquially
Geyser.
Fridge
The
Refrigerator is used for storing eatables at low temperature to keep it fresh
and avoid spoiling due to bacterial activity. Cooling is achieved by using
characteristic behavior of refrigerant (gas) while compression and expansion.
So compressor is an essential component of the refrigerator. It may be rotary
or linear compressor but it is operated by AC or DC electric motor. Ultimately
electricity is used for achieving cooling in the refrigerator.
Refrigerator is working as heat pump. It captures heat from inside compartment and throws it out in surroundings through condenser. The heat released in surrounding is sum of heat captured from the inside compartment plus the heat produced by compressor and motor. The heat so released in open is a waste and raise room temperature that is uncomfortable to the occupants.
Geyser
is used for heating water for various household applications including bathing.
Heat is produced by using electrical energy or other type of fuel for heating the
water. Means energy is spent for heating purpose.
It is seen that fridge release heat as waste while geyser use energy for producing heat. Functions of above two gadgets are complementary. Waste heat of fridge can be utilized for heating water. Merger of fridge and geyser can be energy saving arrangement.
This being combination of Fridge and Geyser, it is identified as Fridgeyser. This can be illustration of cascade utilization OR waste recovery.
Modifications
Condenser
of the fridge has to be heat exchanger. It may be shell and tube type parallel
flow heat exchanger. Hot refrigerant will flow through parallel pipes
surrounded by water in the shell. In regular fridge the hot refrigerant enter
the condenser from bottom and leave from top. Cooling of condenser is air
natural (AN) type. Cold air enters around the condenser from the bottom and
rise upward on getting lighter due to rise in temperature. Air flow is natural
by convection. Generally forced draught using air fan is not common. Here the refrigerant
and cooling water flows in the same direction from bottom to top known as concurrent
parallel flow system. Heat exchanger shown in the sketch is similar type. However
it can be counter current flow type for better performance. Wherein refrigerant
will flow from top to downward and cooling water will flow as it is from bottom
to upward. Refrigerant is flowing due to force of compressor and hence it is
possible to have direction of flow as desired. But flow of cooling water is by
natural convection and hence its direction may be from bottom towards top only.
Heat
exchanger shell is connected to hot water conservator from top and bottom by
piping. Conservator also has outlet piping for drawing hot water and inlet
piping for water topping. Whole hot water system comprising condenser
conservator and piping are heat insulated.
Energy Saving
Cooling will be better in heat exchanger as water is better media compare
to air. Compressor operating time is reduced due to fast cooling in
refrigerator. Coefficient
of Performance
of refrigerator improves requiring less energy for same cooling effect. On the
other hand, hot water is available without consuming energy as waste heat is
utilized for heating water.
So energy saving is in both the units. Energy consumption of refrigerator is reduced. Hot water is available as by product without using energy. Also use of these gadgets is in most of the houses throughout the year. Total energy saving is expected to be very big.
Normal
refrigerator is releasing heat in the air around the condenser. So room temperature
increases. It may be uncomfortable to
occupant and operate fan to get relief from hot air. This is indirect additional
energy consumption in normal refrigerator. In case of AC room, this may be
additional heat load on AC and consume more energy. But such situation is avoided
in proposed fridgeyser and is also indirect energy saving.
Test
piece was fabricated using old fridge as shown in the picture. Condenser was enclosed
in chamber fabricated using GI sheet and was covered by thermocole. Big plastic
jar covered with thermocole was used as water conservator. PVC pipes were used
for water circuit. Performance was encouraging. Cooling was fast and
compressors operating time was reduced. There was significant temperature rise in
conservator water. We could not take it to standard laboratory for exact assessment
of saving as it was not feasible to transport being very delicate.