Humidity Definition and 128 Threads

Is this a way to "humidify" your house? Will boiling water create humidity?

Homework Statement Room temperature is 200C and relative humidity is 60%. what is the absolute moisture Homework Equations Vapor pressure at 200C=17.5[atm] PV=nRT Molecular weight of water=18[gr/mol] The Attempt at a Solution The vapor pressure at 200C: $$\frac{x}{17.5}=0.6\rightarrow...

I recently got heavier into cigar smoking and want to start storing cigars at home in a humidor. Like most things that become a sort of hobby of mine, I research the hell out of my new fascination. So while learning about humidors, I discovered that the cigar community is split on whether or...

Hello Is there any way that RH over water in a closed container could not be 100%? Assuming that the walls of the container are at the same temperature as the contents, that sufficient time has gone by for uniform diffusion of water vapour, that we are at usual room temperatures and...

Why does humidity in the houses make clothes mildew? Is there any method for protection?

Homework Statement A room with volume 2000 cubic metres has air at T=25degrees Celsius with relative humidity 80%. Density of water vapor in saturated air at 25deg Celsius is 22.8g/m^3. Temperature and pressure of room remains constant. What mass of water vapor must be removed from this air to...

Homework Statement A tube (both ends open, height h, diameter d) is immersed into water so that length h1 of the tube is above water. Then the top of the tube is covered tightly and the tube is pulled out of the water so that length h2 is above water. The relative humidity of air is \phi and...

Can anyone help me with the below? Air is drawn into a compressor at normal temperature and pressure (N.T.P) and compressed to a pressure of 6 bar gauge. After compression the air is delivered at 1.2 m3 min-1 and cooled to a temperature of 30°C, at which point condensate is collected at the...

How does humidity affect conductivity of air? I am asking this that because I read that dry air is better insulator than normal air.

Homework Statement We have a saturated vapor mixture with relative humidity 80% at a termpature of 30 C. Find the specific enthalpy of the mixture. Homework Equations The Attempt at a Solution I missed a lecture and a session due to illness and have fallen behind. We are allowed...

This isn't homework, I'm a hobbyist, not a student. Posting here because questions I've previously posted were moved to this section. My intent is to better understand humidity and it's role in compressed air for an automotive application. All help and direction is greatly appreciated. Thank...

I have to design a system to increase the relative humidity in a bunker. I would like to use a spray nozzle and service water. How could I determine how much the relative humidity would raiser per volume of water sprayed into the bunker. Known: - Volume of Bunker - Temperature - Initial...

Homework Statement A pharmaceutical company operating a tabletting facility in Puerto Rico requires stringent environmental control set at 20°C and 40%RH in order to provide consistent high quality production. The HVAC system is designed to cope with outdoor tropical conditions of 30°C and 90%...

Hello all, Would appreciate some guidance here. I have an air compressor compressing ambient air to 3000 psi into a 425cu-in tank. I have the volumetric flow rate at the exit. If I was looking for relative humidity, dew point, and moisture content/accumulation at the exit, how would I go...

Hi, The more humid it is, the more irritable the climate will be. The sweat will not evaporate easily if the relative humidity is high. I have been to two cities in two different countries recently - Madison in USA and Kolkata in India. The humidity in Kolkata is about 65% and that in Madison...

Humidity is known as mass of water vapor/mass of dry air Hs (saturation) = (Mw/Ma){Ps/(P-Ps)} P is total pressure Ps is saturation pressure what is the derivation for this equation?

Homework Statement The air is at 50% humidity and the temperature of the surface of the ocean and the air is 20degrees C. What are the two critical processes that must occur to ensure there is continued evaporation in the absence of external energy sources? Homework Equations Relative...

In sauna rooms, people spend time in conditions of air temperature over 90° C (194° F) with a relative humidity near 10%. However, if you stick your arm into liquid water that is at a temperature of 90° C (194° F), you will be severely burned in less than one minute. Give two reasons why...

For my thermodynamics energy project, we are designing a heat- and cooling installation for an office. We are curious whether the outside air humidity plays a big enough roll in the radiation of heat (convection or conduction). We can assume that the office is a box (no rooms), but we do have...

Hello all, First off, I would just like to say hello, as I am a new member :) I was hoping for some advice on implementing humidity conversions in code. I have spent about 4-5 days trawling the internet for helpful psychometric functions to help convert relative humidity to absolute...

This is totally pissing me off, I don't know what the heck am I doing wrong. Alright, so I was given a temperature of 30°C at 30% relative humidity. I have to get the absolute humidity- So I used Antoine; log(P)=7.96681-1668.21/(228+30); P = 31.6869mmHg. 0.3 x 31.6869 = 9.41517...

Hi, I've been trying to look up the effects of density and humidity on the speed of sound, and I've been finding conflicting results. Some websites have stated that increased humidity will increase the speed of sound because of decreased density in the air, but wikipedia's speed of sound article...

hello guys if the water surface is at same temp as air above, and humidity is 100%, do any wataer molecules leave their liquid state to become vapour ie evaporate? I couldn't remember what professor said exactly, so i checked up on internet and it says water can't evaporate at 100%...

Why doesn't Sound depend on pressure while depends on Humidity ?

Hello, A project I am working on currently requires me to test how capacitors in our circuit react to change in Humidity. As expected, the experimental results suggest that capacitance goes up with increasing humidity, as the electric permitivitty of air surrounding capacitor increases...

[b]the total load in the conditioned space is equal to 320 mBh with a sensible heat ratio equal to 0.90. Outside air equal to 20% of the blower air volume will be used for ventilation. The space setpoint is 75°F db, 45% relative humidity. The outdoor air is 90°F db, 78°F wb. What relative...

Homework Statement Air/Water vapor mixture, at 26C and 45%RH. What is the Dew-point temperature Homework Equations Tdp = Tsat when pg=pv RH = pv/pg The Attempt at a Solution From the psychrometric chart I can get the Humidity ratio, volume per kg dry air, Enthalpy, and...

I have created a mock up of a humidity chamber which i will soon be integrating into a temperature chamber for undergraduate project. I am confused on how i can control the system. I have currently a humidifier with a relay built in, this relay is going to switch on and off from a PWM signal...

Hello everyone... Since this is my first post, I'll intro myself as a Physics major some 40 years ago, who never got around to actually practicing physics and ended up as a Heating/Cooling serviceman...well, I'm a one-truck-service-company-owner and I drive the truck. :biggrin: To the...

Hello, This is my first post on here, so thank you in advance for your help. Homework Statement I have an air tight vessel that has a volume of 1m^3. The bottom of the vessel has water in it. What internal pressure is needed inside the vessel to achieve a temperature of 45C and...

In a calculation I am getting relative humidity more than 100%. What does it suggests? I know this means liquid water is also present in addition to saturated vapour. How should I calculate liquid water content then? Do I have to calculate activity first? Also what happens when I am considering...

1. The problem I need some help in a car tuning project I'm doing, please! I have a turbo charged engine and I have fitted water injection to cool the air charge entering the engine. The idea being that cooler air is more dense and allows more fuel to burn. I need help to calculate the...

as we know at zero degree temp. water condense to form ice. so what will be the relative humidity of a chamber at a temperature below zero degree temp.? will it be nagative or what?

Homework Statement A volume Vi = 29.9 L of air at temperature T = 23 °C is compressed at constant temperature to a volume Vf = 5.6 L. The relative humidity of the air before compression is R = 57.9 %. Saturated water vapour in air at this temperature has a vapour pressure vp = 2.83 kPa and a...

Good day, i am trying to calculate how much water i need to raise air humidity for condensate to apear. i use formula from psychrometric chart : humidity ratio g/kg * volume(m3)/volume m3/kg = volume of water needed. (18-15)*0.032/0.86=0.112g so as i understand i need 0.112g of water...

Hi, I am looking for a graph or function that shows how much water the air can contain as a function of temperature (I think the warmer it is, the more water the air can contain, but I'd like to see an exact graph or function). Thanks! MD.

Why does triboelectric charge accumulation increase with a decrease in humidity? Is the inhumid air less conductive and allow a greater charge difference, or do dissimilar materials when rubbed against each other or pulled apart develop a greater potential difference than when they are in a...

I'm trying to understand the differences (if there are any) between steam, water vapor, and humidity. First of all, is there any difference between the meanings of the terms steam and water vapor? Is there a difference between the terms "gas" and "vapor" in general? Also, I was under the...

Hi, I would like to find the properties of humid air at different humidities and different temperatures. What sort of charts should i consult? I tried looking at psychrometric charts, I'm not sure if I'm reading the correct thing. Thanks

Hi Please explain the effect of humidity on the breakdown voltage of gases including air. Is the relationship linear or non-linear.

I have two questions/ideas about the efficiency of A/C's that I'd like to bounce off you guys. I couldn't find anything on Google about either of these items being discussed before. 1) Precooling The first thought I was wondering was whether it was more efficient to pre-cool your house in...

Homework Statement After taking a deep breath, the mass of air expelled when I exhale is approximately 2.5g. The intake air is at 18deg dry bulb temperature at 60% relative humidity, and the air exhaled is at 100% relative humidity at a temperature of 32deg. The net mass of water expelled...

So, I just received my 3x barlow lens in the mail and let my scope sit outside for two hours to adjust..later I realize the humidity is 80-90% and my scope (6" dob) is literally dripping. Other than moving to Arizona, is there a practical solution to this problem?

Hi there, I'm trying to calculate air density; I noticed on http://en.wikipedia.org/wiki/Density#Density_of_air" that there is a table that makes it seem that air density is a function of temperature... I suppose I could safely say that temperature has a significant effect on air density...

hello all, We live in a hot part of the world with the extra bonus of high humidity - around 90%. We don't have A/C, and don't really want to get it (energy use). Evaporative cooling won't do much (towel on head) becuase of water saturation in air. Would a cold wet towel + fan force water...

Does the viscosity of air change with change in the degree of humidity at room temperature?

Homework Statement the air temperature is -15 degrees Celsius and the relative humidity is 70 per cent. If the air is brought indoors and heated to 20 degrees Celsius with no added moisture, what is the new relative humidity? Homework Equations RH=e/es x 100% or ws=epsilon*es/p...

Homework Statement If a person breathes 10 liters per minute of air at 68 degrees F and 50% relative humidity, how much water per day must the internal membranes supply to saturate the air at 98.6 degrees F. (assume all the moisture is exhaled) If each gram of water extracts 580 calories as...

Homework Statement The temperature of a room is 25 degree Celsius and its relative humidity (RH) is 60%.If the temperature is lowered to 15 degree Celsius,what fraction of water vapor gets condensed? Saturated Vapour Pressure(SVP25)at 25 degree celsius = 23.7mmHg S.V.P.15=12.8mmHgHomework...

Homework Statement Temperature of a closed room is 15 degree celsius (T288).Relative humidity(RH)at 15degree celsius =60% Find the RH when the temperature is 20 degrees. S.V.P at 15 degrees celsius=12.67mmHg SVP at 20 degree celsius = 17.36mmHg (ans:45%) Homework Equations The...