I had a 28 bottle Vino Temp cooler I was using to keep my sticks in, the control card died so it is OOS. I was never really happy with the unit anyway, when it lost power the temp went low, and it was bad about condensing moisture from the peltier. I had modified the inside of the cooler by putting a piece of luan just on the back side of the drawers from side to side with a gap at the top and bottom, and the top shelf was solid that I cut a hole in and installed a computer fan to move air from the bottom, though the drawers, out the top and past the peltier, back to the bottom. The air circulating seemed to help condensation. I would attach pictures if I knew how.
I am installing my own control system. The 12 Volt supply is working on the cooler. I am using an Arduino Uno, with a motor control card, it reads the temperature and relative humidity of air inside the unit, shows them on a 20x4 LCD screen. I attached a thermistor to the peltier to read the temperature of the peltier, and the Arduino uses that temperature to control the peltier so the cooling temperature is above the dew point. The original control card turned the thermoelectric device on at 40-45 degrees F, and trying for 70 degrees F, and 65% relative humidity, the dew point is about 54 degrees F so condensation occurs. The peltier has to run longer above the dew point, but it does not condense moisture out of the air. The arduino also controls the cold side fan of the peltier, and the hot side fans. The uno runs the computer fan on the top shelf at 50% when peltier is off and 100% when peltier is on.
I purchased everything I needed for the new control for about $30-40.
I have read a lot of threads about Temp and relative Humidity, it is funny cigar smokers are into the engineering science of psychometrics,
the study of the physical and thermodynamic properties of gas and vapor mixtures. You can probably get a four year college degree in this area of science, it is not surprising how confusing it is. What I gleaned from all the reading. There are 3 different measures of humidity, absolute, relative, and specific humidity.
Absolute humidity is the water content of air expressed in gram per cubic meter.
Relative humidity, expressed as a percent, measures the current absolute humidity relative to the maximum (highest point) for that temperature. 100%RH at any given temp is the Dew Point,
Specific humidity is the ratio of the mass of water vapor to the total mass of the moist air parcel.
We measure relative humidity %RH, and that will confuse the situation because that RH number is dependent on temperature. Basically the cooler is sealed if you have the drain plugged. You have the same amount of moisture particles in the same volume of air, but the relative humidity will change as temperature rises and lowers. Warm air expands and can hold more moisture so the relative humidity lowers, cold air can not hold as much moisture, so relative humidity rises as temperature lowers. The relative humidity changes as the temperature rises and lowers, but there is the same amount of moisture particles in the air. The first part of the calculation for RH is absolute humidity, or how many moisture particles are present, what changes is the maximum amount of moisture at a given temperature, effects the ratio.
It is the amount of available moisture particles that keep the sticks right to burn one off.
An example- relative humidity of 60% at 80 degrees, there are 90 grains of moisture per pound of dry air. Relative humidity of 60% at 60 degrees there are 55 grains of moisture per pound of dry air. Relative humidity is the best indication we have, but it is all about moisture content. You just have to keep in mind when you look at the temperature and relative humidity indication how the two affect each other. The temp and RH indications may be changing but that does not indicate the amount of moisture particles is changing.
So the new control system I am using controls temperature as consistently as possible and does not remove moisture by condensation so it should keep RH consistent too.
I would share pictures if I knew how.
I am installing my own control system. The 12 Volt supply is working on the cooler. I am using an Arduino Uno, with a motor control card, it reads the temperature and relative humidity of air inside the unit, shows them on a 20x4 LCD screen. I attached a thermistor to the peltier to read the temperature of the peltier, and the Arduino uses that temperature to control the peltier so the cooling temperature is above the dew point. The original control card turned the thermoelectric device on at 40-45 degrees F, and trying for 70 degrees F, and 65% relative humidity, the dew point is about 54 degrees F so condensation occurs. The peltier has to run longer above the dew point, but it does not condense moisture out of the air. The arduino also controls the cold side fan of the peltier, and the hot side fans. The uno runs the computer fan on the top shelf at 50% when peltier is off and 100% when peltier is on.
I purchased everything I needed for the new control for about $30-40.
I have read a lot of threads about Temp and relative Humidity, it is funny cigar smokers are into the engineering science of psychometrics,
the study of the physical and thermodynamic properties of gas and vapor mixtures. You can probably get a four year college degree in this area of science, it is not surprising how confusing it is. What I gleaned from all the reading. There are 3 different measures of humidity, absolute, relative, and specific humidity.
Absolute humidity is the water content of air expressed in gram per cubic meter.
Relative humidity, expressed as a percent, measures the current absolute humidity relative to the maximum (highest point) for that temperature. 100%RH at any given temp is the Dew Point,
Specific humidity is the ratio of the mass of water vapor to the total mass of the moist air parcel.
We measure relative humidity %RH, and that will confuse the situation because that RH number is dependent on temperature. Basically the cooler is sealed if you have the drain plugged. You have the same amount of moisture particles in the same volume of air, but the relative humidity will change as temperature rises and lowers. Warm air expands and can hold more moisture so the relative humidity lowers, cold air can not hold as much moisture, so relative humidity rises as temperature lowers. The relative humidity changes as the temperature rises and lowers, but there is the same amount of moisture particles in the air. The first part of the calculation for RH is absolute humidity, or how many moisture particles are present, what changes is the maximum amount of moisture at a given temperature, effects the ratio.
It is the amount of available moisture particles that keep the sticks right to burn one off.
An example- relative humidity of 60% at 80 degrees, there are 90 grains of moisture per pound of dry air. Relative humidity of 60% at 60 degrees there are 55 grains of moisture per pound of dry air. Relative humidity is the best indication we have, but it is all about moisture content. You just have to keep in mind when you look at the temperature and relative humidity indication how the two affect each other. The temp and RH indications may be changing but that does not indicate the amount of moisture particles is changing.
So the new control system I am using controls temperature as consistently as possible and does not remove moisture by condensation so it should keep RH consistent too.
I would share pictures if I knew how.
