EcoRenovator - View Single Post - Essential question of humidity vs temperature

osolemio · 10-05-12, 08:20 PM

In climates, where it is too hot for comfort, we often need cooling - air conditioning - to keep us comfortable inside.

In almost all installations, a heat pump is splitting the energy of the air into hot and cold, directing the hot outside and cold inside. Most often, the air is cooled to not much over the freezing point (of water), and the temperature of the air is what is keeping the entire house cool - not just the air. Ideally. Ironically, at the same time as heat is expelled, heating up the outside even more, other energy sources are often used for hot water, like electricity, oil, propane ... what a waste!

Well, so far so good.

But really, we are so focused on temperature, for comfort. In the setup above, moisture is taken from the air inherently, as air being cooled off means decreasing the amount of moisture it will hold. As such, a normal air condition unit is also at the same time, a humidifier, hence, we don't really consider the humidity very much - the main parameter is TEMPERATURE in the control of our comfort.

But there is much more to comfort than just fahrenheit and centigrades.

HUMIDITY in itself is a highly forgotten parameter. Add to that CIRCULATION of air, and even think of different requirements for bedrooms, kitchens, gyms, offices ... there isn't just one golden target of temp/hum/airflow which suits all, different activities demands different environments.

In the winter mainly, we discuss WIND CHILL factors - more wind at the same temperature is factored, when a body is kept at a different temperature to the surroundings, ie the human body around 100F in much colder surroundings. The same goes for a building, whether heating in the winter, or cooling in the summer - more wind means more exposure - but ONLY when there is a difference in temperature. If the air temperature outside is close to the temperature of the house, more of less wind has no "wind chill" (or heating) effect.

The same for the inside environment of the house, circulation of air means (in most cases) more cooling of bodies - hence we often use plain fans, where real cooling isn't available, or in a non-A/C car, open the windows.

HUMIDITY ... just like the wind chill, you can make a table where temperature and humidity are interrelated to form an "index", like the Canadian Humidex: Humidex - Wikipedia, the free encyclopedia - (there are other ways of measuring it).

In other words, my claim is that for ENERGY CONSERVATION and INCREASED COMFORT, we should look more at air flow and humidity control, NOT just temperature.

If we can control the moisture content of the air, a much wider range of temperatures are comfortable. And frankly, coming from a hot moist outside into a cold, dry, drafting inside, can be quite a shock to the body, sometimes sparking summer colds, and other discomforts.

What we REALLY NEED is to find the "cheapest" way (energy-wise) to

REMOVE MOISTURE FROM AIR

Not heating, not cooling, not looking at the relative humidity, but how to wringe the air, the most energy efficient way. Add pain fans, which use a lot less energy than "real A/C", and we can have a comfortable environment using far less energy than a normal A/C HVAC installation.

So help me here, what is the best way?

Silica / dissicant liquid?
Solar heat driven heat pumps?
Conventional electric dehumidifiers?
Other solutions ... ?

My postulate is, that many buildings can save lots of electricity using less A/C, if we find a proper way to remove the moisture, and keeping the temperature HIGHER than the usual ~70F / 21C. Even 80F is comfortable, if the air is sufficiently dry. 90F is not optimum but bearable, if the air is really dry.

But we really need ... a reliable, cheap and efficient method, to remove moisture, which uses a minimum amount of energy.

Please add your comment below, with your best take on this.

Thank you.

10-05-12, 08:20 PM	#1
osolemio Hong Kong Join Date: May 2010 Location: Hong Kong Posts: 108 Thanks: 20 Thanked 17 Times in 13 Posts	Essential question of humidity vs temperature In climates, where it is too hot for comfort, we often need cooling - air conditioning - to keep us comfortable inside. In almost all installations, a heat pump is splitting the energy of the air into hot and cold, directing the hot outside and cold inside. Most often, the air is cooled to not much over the freezing point (of water), and the temperature of the air is what is keeping the entire house cool - not just the air. Ideally. Ironically, at the same time as heat is expelled, heating up the outside even more, other energy sources are often used for hot water, like electricity, oil, propane ... what a waste! Well, so far so good. But really, we are so focused on temperature, for comfort. In the setup above, moisture is taken from the air inherently, as air being cooled off means decreasing the amount of moisture it will hold. As such, a normal air condition unit is also at the same time, a humidifier, hence, we don't really consider the humidity very much - the main parameter is TEMPERATURE in the control of our comfort. But there is much more to comfort than just fahrenheit and centigrades. HUMIDITY in itself is a highly forgotten parameter. Add to that CIRCULATION of air, and even think of different requirements for bedrooms, kitchens, gyms, offices ... there isn't just one golden target of temp/hum/airflow which suits all, different activities demands different environments. In the winter mainly, we discuss WIND CHILL factors - more wind at the same temperature is factored, when a body is kept at a different temperature to the surroundings, ie the human body around 100F in much colder surroundings. The same goes for a building, whether heating in the winter, or cooling in the summer - more wind means more exposure - but ONLY when there is a difference in temperature. If the air temperature outside is close to the temperature of the house, more of less wind has no "wind chill" (or heating) effect. The same for the inside environment of the house, circulation of air means (in most cases) more cooling of bodies - hence we often use plain fans, where real cooling isn't available, or in a non-A/C car, open the windows. HUMIDITY ... just like the wind chill, you can make a table where temperature and humidity are interrelated to form an "index", like the Canadian Humidex: Humidex - Wikipedia, the free encyclopedia - (there are other ways of measuring it). In other words, my claim is that for ENERGY CONSERVATION and INCREASED COMFORT, we should look more at air flow and humidity control, NOT just temperature. If we can control the moisture content of the air, a much wider range of temperatures are comfortable. And frankly, coming from a hot moist outside into a cold, dry, drafting inside, can be quite a shock to the body, sometimes sparking summer colds, and other discomforts. What we REALLY NEED is to find the "cheapest" way (energy-wise) to REMOVE MOISTURE FROM AIR Not heating, not cooling, not looking at the relative humidity, but how to wringe the air, the most energy efficient way. Add pain fans, which use a lot less energy than "real A/C", and we can have a comfortable environment using far less energy than a normal A/C HVAC installation. So help me here, what is the best way? Silica / dissicant liquid? Solar heat driven heat pumps? Conventional electric dehumidifiers? Other solutions ... ? My postulate is, that many buildings can save lots of electricity using less A/C, if we find a proper way to remove the moisture, and keeping the temperature HIGHER than the usual ~70F / 21C. Even 80F is comfortable, if the air is sufficiently dry. 90F is not optimum but bearable, if the air is really dry. But we really need ... a reliable, cheap and efficient method, to remove moisture, which uses a minimum amount of energy. Please add your comment below, with your best take on this. Thank you. __________________ Space heating/cooling and water heating by solar, Annual Geo Solar, drainwater heat recovery, Solar PV (to grid), rainwater recovery and more ... Installing all this in a house from 1980, Copenhagen, Denmark. Living in Hong Kong. Main goal: Developing "Diffuse Light Concentration" technology for solar thermal.