Increasing Airflow through Condenser.
The new DC only compressor fridge I will soon have in my possession has a 92 mm computer muffin fan pulling air through only a portion(~85%) of the ~120mm tall condenser. It then blows this warmed a...
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Well, I am no longer considering changing the direction of flow through the condenser. I am just going to make sure the fan is not recycling heated air. I might, perhaps, get a equal CFM fan with dual ball bearings instead of the sleeve bearings.
The hot pipe which comes out from the compressor at around 95 degrees goes in a full loop, right in the strongest flow of the fan before entering the top of the condenser at 83 degrees, it comes out the bottom of the condenser at 72 degrees, which is about 1 degree above ambient temps at the moment.
So it loses more heat in the first loop before it enters the condenser, than the amount of heat it loses going through the condenser. I'd be a fool to reverse the flow.
The compressor body itself is hotter than the condenser, at least during this cool down stage.
The interior has not quite gotten all the food below 40 yet. My Ir gun is showing exterior the sides of the fridge at the bottom are 4 to 5 degrees below ambient, the bottom of the door is 2 below degrees ambient. The bottom back is at ambient. Top of the exterior is at ambient.
The insulated line which exits the fridge is 15 degrees below ambient.
I think the extra insulation on the sides and bottom will help significantly. Not much I can do for the door.
Right now, while it is still cooling down inside, it is running nearly 4 minutes on, and a little over 5 minutes off, with the thermostat set in the middle. It starts out pulling 3.6 amps quickly drops to 3.1 and is down to just 2.8 amps when it shuts off.
I tried it without the resistor for a few cycles. It started at 2.6 amps and finished below 2 amps.
Edit: A few hours later the box was only slowly getting colder but the freezer was at -12f. Since I still had the wiring for my previous interior fridge fan in place. I installed the fan in the freezer box, just closing the door on the 22 awg wires. Within an hour the freezer was 12f, and the box temps were below 34 in most areas. Directly below the coldplate, it was 29 degrees.
I backed off the thermostat, it now rests at a third of max. 12 f Freezer, 35f box temps +/- 2f. Last 3 cycles were 4:25 on, 9:45 off, so less than a 33% duty cycle at 66 degrees ambient. There is an audible click when it cycles on or off, so checking duty cycle seated next to is is easy.
I am going to wire in the interior fan to run 24/7 and not go through the door seal. It made a huge difference. I think perhaps with more insulation, the resistor and higher compressor speed is not needed, nor such a high CFM fan. Other fridges with the same size compressor and evaporator use a smaller 38 cfm fan and no resistor. Perhaps this fridge is overpowered for fast cool down.
The hot pipe which comes out from the compressor at around 95 degrees goes in a full loop, right in the strongest flow of the fan before entering the top of the condenser at 83 degrees, it comes out the bottom of the condenser at 72 degrees, which is about 1 degree above ambient temps at the moment.
So it loses more heat in the first loop before it enters the condenser, than the amount of heat it loses going through the condenser. I'd be a fool to reverse the flow.
The compressor body itself is hotter than the condenser, at least during this cool down stage.
The interior has not quite gotten all the food below 40 yet. My Ir gun is showing exterior the sides of the fridge at the bottom are 4 to 5 degrees below ambient, the bottom of the door is 2 below degrees ambient. The bottom back is at ambient. Top of the exterior is at ambient.
The insulated line which exits the fridge is 15 degrees below ambient.
I think the extra insulation on the sides and bottom will help significantly. Not much I can do for the door.
Right now, while it is still cooling down inside, it is running nearly 4 minutes on, and a little over 5 minutes off, with the thermostat set in the middle. It starts out pulling 3.6 amps quickly drops to 3.1 and is down to just 2.8 amps when it shuts off.
I tried it without the resistor for a few cycles. It started at 2.6 amps and finished below 2 amps.
Edit: A few hours later the box was only slowly getting colder but the freezer was at -12f. Since I still had the wiring for my previous interior fridge fan in place. I installed the fan in the freezer box, just closing the door on the 22 awg wires. Within an hour the freezer was 12f, and the box temps were below 34 in most areas. Directly below the coldplate, it was 29 degrees.
I backed off the thermostat, it now rests at a third of max. 12 f Freezer, 35f box temps +/- 2f. Last 3 cycles were 4:25 on, 9:45 off, so less than a 33% duty cycle at 66 degrees ambient. There is an audible click when it cycles on or off, so checking duty cycle seated next to is is easy.
I am going to wire in the interior fan to run 24/7 and not go through the door seal. It made a huge difference. I think perhaps with more insulation, the resistor and higher compressor speed is not needed, nor such a high CFM fan. Other fridges with the same size compressor and evaporator use a smaller 38 cfm fan and no resistor. Perhaps this fridge is overpowered for fast cool down.
