7 votes
Accepted

Why is it generally assumed that the evaporator works isothermally?

Assuming you mean evaporator as part of a vapour compression cycle, then because the fluid enters as a liquid and leaves as a gas, which means that the temperature can be the same but the internal ...
Solar Mike's user avatar
  • 15.7k
5 votes

What would be the best setup to evaporate as much seawater as possible using the propane from a 1kg tank?

Since the amount of energy per unit volume required to evaporate (or boil, depending on your desire for speed) the water is a constant, the only things to control are, roughly: efficiency of heat ...
Carl Witthoft's user avatar
3 votes

why not put the compressor right next to the evaporator?

The evaporator is usually in the area to be cooled ie where the people work, read etc As the compressor takes space and tends to be noisy it is located away from that area. That makes the system in ...
Solar Mike's user avatar
  • 15.7k
2 votes

Exiting air temperature in direct evaporative cooler vs cooling tower

Mixing two media (air and water) just averages the temperature between them (proportionally to their respective heat capacities and total volumes) - through classic conduction. Additionally, ...
SF.'s user avatar
  • 6,105
2 votes
Accepted

Why do a swamp cooler and dehumidifier effectively cool a room when paired together in an enclosed space?

Please note the following fact about dehumidifiers: A dehumidifier is basically a room air conditioner which works by cooling the inlet air down just to the point where the water dissolved in it ...
niels nielsen's user avatar
2 votes

why not put the compressor right next to the evaporator?

What you describe is quite common where there isn't any problem with power and noise. It requires a bit more sophistication to manage the superheat. And yes, you need to quiet the thing some. I ...
Phil Sweet's user avatar
  • 4,755
1 vote

How can some clouds be removed from the sky?

Speaking hypothetically... you could make the mirrors sufficiently steerable to aim reflected sunlight at the pesky clouds, raising their temperature and vaporizing the water droplets. But that won't ...
niels nielsen's user avatar
1 vote

How can some clouds be removed from the sky?

Work out which way the wind usually blows where you are. Build a large mountain range between you and the sea in that direction. Most of the rain clouds will drop their rain onto the mountains, ...
Simon B's user avatar
  • 214
1 vote

Will water boil from top-down radiant heating?

It is practically difficult to get water to boil without what is known as nucleation sites. Tiny imperfections in the heated wall provide increased heat transfer surfaces. Pyrex containers in a ...
Tiger Guy's user avatar
  • 6,871
1 vote

Homemade spray dryer - how to generate powerful hot air?

I would start from the amount of liquid being sprayed, because your goal is to evaporate the liquid and leave the solute(powder). Once you know that you can calculate the heat required to add to the ...
NMech's user avatar
  • 24.3k
1 vote

Homemade spray dryer - how to generate powerful hot air?

Start with specifications. What temperature, what flow rate, from those two and the specific heat capacity of air you can work out the power required. $$ P = \Delta T \times m \times SHC $$ where $P$ ...
Transistor's user avatar
  • 10.7k
1 vote

How could I automatically agitate water by blowing warm air over its surface?

If your primary objective is to increase evaporation, you are more likely to decrease the temperature of the water rather than increase it. If you can accept the reduction of temperature, consider ...
fred_dot_u's user avatar
  • 7,097
1 vote

How to dump moist air without heat backflow in evaporative cooling system?

I'm not an expert on swamp coolers, but I would try to keep all the evaporation outside of your dorm room. Here's an example: You build a heat exchanger between inside and outside, then you mist the ...
Drew's user avatar
  • 1,931
1 vote
Accepted

Calculate amount of evaporative coolers needed to cool down an area

Foundations (Energy Balance) For the Room Consider the system shown in the picture below. Air flows through a room volume (area and height) with a residence time. Heat is provided by people inside ...
Jeffrey J Weimer's user avatar
1 vote
Accepted

Is evaporative cooling for a pool effective?

I'm going to take the formal question statement as "Is evaporative cooling for a pool effective?" There are a handful of factors that need to be considered. First and foremost though, is wet ...
ChemE mang's user avatar
1 vote

Water vacuum evaporation thermodynamics

The temperature sounds correct, the energy balance does not. I get 405°C for the compressor discharge but the enthalpy increases from 2547 kJ/kg to 3289 kJ/kg, for a work input to the gas of 743 kJ/kg,...
ericksonla's user avatar
1 vote

Is Vapor Compression Distillation inherently more efficient than a thermal-only boiler-condensor?

No, no, no, guys. Vapor compression recovers the latent heat of condensation that is normally lost to cooling water in a condenser. It does this by taking vapors that would normally go to a condenser ...
Bill Schafer's user avatar
1 vote

Evaporative roof cooling

What is the general range of relative humidity? You won't get anywhere unless the air is reasonably dry. Next, you want to maximize the evaporative area or most of the water will just roll off the ...
Carl Witthoft's user avatar
1 vote
Accepted

Optimum airflow for drying with heated air

If you are only interested in temperature, flow rate, and drying rate, then you could consider the following quantities for a given air temperature $T$: How much heat you need for evaporation (based ...
Han-Kwang Nienhuys's user avatar

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