Water, humity, temperature questions

In summary, a room with dimensions of 30 square meters and a height of 2.5 meters that is completely insulated and at a temperature of 25 degrees Celsius and 30% relative humidity has 10 liters of water at the same temperature poured onto the floor. The question is whether the temperature of the room will increase due to more energy being added, decrease due to water evaporation and cooling the air, or remain the same as the water is at the same temperature as the air. After discussing the concepts of energy flow and humidity, it is determined that the temperature of the room will decrease as the water evaporates and cools the air, despite the addition of energy to the system. This is due to the fact that temperature
  • #1
jamesabc
22
0
say there is a room 30 square meters by 2.5 meters high, completely insulated. if the room is at 25 degrees Celsius and 30% relative humidity then suddenly you bring in 10 liters of water at the same temperature and pour it on the floor; question is will the temperature of the room increase due to more energy being put in the room, decrease due to water evaporating and cooling the air, or stay the same as water is at same temperature as the air.
 
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  • #2
Sounds like homework. What do you think the answer is and why?
 
  • #3
russ_watters said:
Sounds like homework. What do you think the answer is and why?

it actually isn't homework, i have completed a BE in mechanical about a year ago, i was just thinking about humidity and how it works.

i guess temperature would go up as you are adding more energy to the room, that's if the water has more energy at 25 degrees than air. that's what i think.
 
  • #4
And how did that energy flow from 25°C fluid to 25°C air? Heat spontaneously flows from hot to cold. Always. No exceptions.

On the other hand, humidity is the rate of evaporation vs rate of condensation. At 100%, they are equal. Bellow that, evaporation is faster. Water at 25°C won't stay at that temperature in a 30% room. Work out what happens to the water, and you'll have your answer.
 
  • #5
jamesabc said:
it actually isn't homework, i have completed a BE in mechanical about a year ago, i was just thinking about humidity and how it works.

i guess temperature would go up as you are adding more energy to the room, that's if the water has more energy at 25 degrees than air. that's what i think.

If you have completed a degree and ME and still can't figure this out, it is sad.

Temp. will decrease, that is the answer.
 
  • #6
K^2 said:
And how did that energy flow from 25°C fluid to 25°C air? Heat spontaneously flows from hot to cold. Always. No exceptions.

On the other hand, humidity is the rate of evaporation vs rate of condensation. At 100%, they are equal. Bellow that, evaporation is faster. Water at 25°C won't stay at that temperature in a 30% room. Work out what happens to the water, and you'll have your answer.

the water would evaporate and reduce the air temperature, floor temperature. but since this is a closed system when you are adding the water to that system which is at the same air temperature inside wouldn't the energy in that system increase? and there fore the room temperature would increase? if I am wrong then I am wrong, asking questions is how you learn
 
  • #7
jamesabc said:
but since this is a closed system when you are adding the water to that system which is at the same air temperature inside wouldn't the energy in that system increase? and there fore the room temperature would increase? if I am wrong then I am wrong, asking questions is how you learn
You're adding energy but you're also adding mass so the average energy doesn't change. Temperature is a function of average energy, not total energy - otherwise a big house would always be warmer than a small house.
 
  • #8
jamesabc said:
the water would evaporate and reduce the air temperature, floor temperature. but since this is a closed system when you are adding the water to that system which is at the same air temperature inside wouldn't the energy in that system increase? and there fore the room temperature would increase? if I am wrong then I am wrong, asking questions is how you learn

Adding "energy" doesn't mean you have higher temperature. You have also changed the heat capacity of the system by adding water. Your reasoning is fallacious.
 
  • #9
but since this is a closed system when you are adding the water to that system which is at the same air temperature inside wouldn't the energy in that system increase?

What is your definition of a closed system?
 

1. What is the ideal humidity level for a comfortable indoor environment?

The ideal humidity level for a comfortable indoor environment is between 40-60%. This range helps prevent dryness and static electricity, as well as mold and mildew growth.

2. How does humidity affect our health?

High humidity can make it difficult for our bodies to cool down, leading to heat exhaustion and dehydration. Low humidity can dry out our respiratory system and cause irritation and discomfort.

3. How does temperature impact the amount of moisture in the air?

Temperature affects the amount of moisture in the air through a process called evaporation. As temperature increases, the rate of evaporation also increases, leading to higher humidity levels.

4. Is it possible for humidity levels to be too low or too high?

Yes, extreme humidity levels, either too low or too high, can have negative effects on our health and the environment. It is important to maintain a balanced humidity level for optimal comfort and well-being.

5. How can I control humidity and temperature levels in my home?

There are several ways to control humidity and temperature levels in your home, such as using a dehumidifier or humidifier, proper ventilation, and adjusting your thermostat. It is also important to seal any air leaks and regularly maintain your HVAC system.

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