This project goes over the conversion of an old three-way refrigerator unit from an RV into an alternative power Off-grid Dual refrigeration system that uses no electric power. This can be really useful in case of a power outage or SHTF situation when you need to keep your food or vegetables fresh.
STEP 1 : REMOVING THE COMPONENTS OF THE OLD REFRIGERATOR
The first step is to strip the fittings on the backside of the fridge, remove all the ammonia system, and clean the inside of it. Here we are incorporating more than one way to use this fridge for the cooling refrigeration system. We will be inducing the cooling effect by bringing down the water temperature to cool the box. Another way to cool the box is by installing an evaporative system. We take the two pipes coming from the water source around the edges of the box and put some cotton sheets around the sides and let the water cascade down the sheet creating an evaporative effect.
STEP 2 : CONNECTING THE FISH TANK PUMP
We have an inverter and a battery attached to the fridge that is hooked up to a 25W solar panel. The wire from the inverter is connected to an 8W Electric Fish tank pump. The water coming from the pump goes underneath and up inside to the lid of the fridge to the condenser coils and then comes back around back into the water source like a well or water tank. The system is recirculated back into the original storage tank where the water is coming from.
STEP 3 : ADDING TWO POLY TUBING COILS
We keep the fridge in a chest freezer style instead of an upright style. Inside the fridge, we have incorporated 2 poly tubing coils attached to an old heat sink that was already in the fridge. The 100ft coils are attached to the top of the fridge. The cold from that coils will drop down to the rest of the fridge.
STEP 4 : INDUCING AN EVAPORATIVE COOLING EFFECT
The next step is to incorporate the evaporative cooling part of the refrigeration system. We start by installing aluminum U channels across all the edges of the fridge. The U channel will hold cotton material inside of them. The water coming out of the outputs from our coils rushes into the channel which is going to wick out into the cloth and run down the cloth with gravity, giving us our evaporative cooling effect.
On the corners, we have the U channels interconnected to each other through a bent garden hose in such a way that any extra water flow in the channel can transfer to the channel that is next.
The cotton sheets are stretched around the box and tuck it down into the channels all the way around under the wires such that the wires will hold the channels up and hold the sheet up inside the channel. To even the flow of the water, we install a tee. Now the water coming from both sides of the channel can leak into the sheet. Also, make sure you have an air gap between the sheet and the refrigerator box.