Post on 25-Feb-2016
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About Neptronic
Established in 1976 in Montreal Canada Design and manufacture innovative HVAC products HQ and manufacturing facility (80,000 sq ft) located in Montreal Worldwide distribution network; present in every continent
HUMIDIFICATION Presentation
WELCOME │ BIENVENIDO │ BIENVENUE
Agenda
1. Introduction to Humidification2. Why Humidity is so Important3. Why Should We Humidify4. Typical Applications5. Calculation Parameters6. Existing Local Variables7. Hardness of Water8. Types of humidifiers
•Isothermal / Adiabatic
9. Isothermal• Electric Humidifier
• Resistive
• Electrode• Gas-Fired Humidifier• Steam to Steam Humidifier • Direct Steam Injection Humidifier
• Multi-Steam Distribution• Jacketed Tube Distribution
10. Adiabatic• Atomizing Humidifier
• Air/Water Fogger• High pressure Water
• Ultrasonic Humidifier• Evaporative Humidifier
Humidity: Water that is in gaseous form, vapour.
Relative humidity (% RH): The amount of vapour in air at a specific temperature with respect to the maximum quantity of steam that can absorb without condensation.
Humidification: This process occurs when the water has absorbed enough heat to evaporate. It requires about 1,000 Btu to evaporate one pound of water (2.326 kJ / kg).
Introduction to Humidification
70% of the planet is covered by water.
The human body is composed of roughly 60% water by volume.The gaseous form of water is vapor and the measure of water vapor in the air we breathe is relative humidity.
The amount of vapor the air can hold is dependent upon the temperature of the air. The warmer the air the more vapor it can hold. The reverse is true for cooler air.
Why Humidity is so Important?
We function best at temperatures between 70 and 80 degrees and relative humidity of 40% to 60%.
If the air is dry and hot we lose body water by evaporation very quickly and thus our skin and sinuses are dry and we are always in need of replenishing the lost water.
Indoor environments in the winter are generally very dry in northern countries and so there is a need to add vapor so that we feel and function better.
Why Humidity is so Important?
All land based animals have similar problems with the relative humidity around them.
In fact just about all material both living and inanimate is affected by the amount of vapor in the air.
Paint, plastics, silicone, paper, textiles etc.; Many manufacturing processes require close humidity and temperature control in order to maintain product quality.
Why Humidity is so Important?
Indoor air quality (Health, Comfort and Productivity)- schools, health care facilities, offices, living space
Material protection and storage- museums, archives, libraries, wood/paper, textiles, food processing
Environments for specific processes- Printing, clean rooms, pharmaceuticals, laboratories, semiconductors- Animal rooms/research, Zoological facilities
Static electricity- computer rooms, data processing areas, hazardous environments, munitions, aerospace,
paint spray booths
Why Should We Humidify?
Optimal Humidity Level
2008 ASHRAE, HVAC Systems & Equipment, Chapter 21By E.M. Sterling, A. Arundel, and T.D. Sterling, Ph.D.
Typical ApplicationMuseums / Libraries
35-50%RHOffices / Hotels / Schools
35-40% RHClean rooms / Data Centers
35-60% RHPharmaceuticals / Labs
40-50% RH
Hospitals / Health Care35-50% RH
Printing Industry40-50% RH
Tobacco Industry60-70% RH
Design Conditions- Outside temperature/RH(%) and desired indoor conditions
Load calculation (lbs/hr) for ventilation system- Natural: Space/Room Size/Number of air changes - Mechanical: Total Air Flow and % of outside air- Economizer: Total Air Flow and Mixed Air Temperature
Distribution- Airflow direction, AHU/Duct size and Absorption Distance - Self contained
Calculations Parameters
• Supply water quality– City or well, softened, reverse osmosis or de-ionized
• Energy source– Electricity, natural or LP gas, boiler steam or chemical-free boiler steam, High temperature hot
water, Evaporative/atomizing
OTHER PARAMETERS TO CONSIDER– Initial investment– Energy cost comparison – Space available– Steam distribution configurations– Maintenance requirements– Vapor barriers
Existing Local Variables
Description: Water is considered a universal solvent. In drinking water there are several minerals that are dissolved.
Hardness is determined by the concentration of calcium and magnesium dissolved in water (ppm). Montreal city water 116ppm
Precipitate: When water evaporates, the minerals create deposits.
Water Treatment: water softeners, reverse osmosis or de-ionized systems
Hardness of Water
Isothermal• Electric Humidifier
• Resistive• Electrode
• Gas-Fired Humidifier• Steam to Steam Humidifier • Direct Steam Injection Humidifier
• Multi-Steam Distribution• Jacketed Tube Distribution
Adiabatic: • Atomizing Humidifier
• Air/Water Fogger• High pressure Water
• Ultrasonic Humidifier• Evaporative Humidifier
Types of Humidifier
Isothermal Humidifiers
Pros Clean sterile steam Compact size Low installed cost Close humidity control If electric generation is close, very efficient
Cons Cost of energy Creates a certain cooling load Limited capacity
Electric Humidifiers
Resistive typePros Permanent cleanable chamber Works in all water qualities Output can be held very close
Cons Required tank cleaning can be
difficult
Electrode typePros Bottle change out is easy and fast
Cons Replacement bottles are expensive Complicated control system wastes too much water Capacity loss as electrodes becomes coated, unit will stop Water quality affects operation and operating cost Bottles are not enviromentally friendly
Electric Humidifiers: Resistive vs Electrode
Pros Clean sterile steam Large capacity available Low energy cost Close control 80-85% efficient
Cons Large foot print Installation requirements (flue
/combustion air) Creates a cooling load Must have gas supply Not good for small loads
Gas Fired Humidifiers
Pros Clean sterile steam Large capacity Closes boiler loop
Cons Must have a central steam supply Large foot print Creates a cooling load Can be difficult to maintain
Steam to Steam Humidifiers
Pros Large capacity Low initial installation cost Close control
Cons Must have a central steam supply Home run steam / condensate Chemical carry over / dirty Open loop for boiler Must keep the steam jacket hot Creates a cooling load
Direct Steam Humidifiers
Direct Steam Injection Humidifier
ConfigurationsMulti-Steam Distribution Jacketed Tube Steam Distribution
Consists of vertical tubes connectedto a header
Short non-wetting distance
Jacket preheats the steam distributor tubes Horizontal distributor installation only Steam nozzles facing the airstream
Adiabatic Humidifiers
Adiabatic humidification
IsothermalHumidification
AdiabaticHumidification
Adding moisture to air can be accomplished with no addition of energy from external source. The air evaporates the water by itself, using a part of its sensible heat to accomplish the task, cooling the air as it absorbs moisture.
As the air absorb moisture and moves up the wet bulb line, the RH and the air temperature are both changing, but the total heat content (enthalpy) remains unchanged.
This natural phenomenon is used to save energy costs by augmenting mechanical refrigeration in warm, arid climates. Buildings are cooled and humidified simultaneously using this principle. It is also used in cold climate when humidification is needed in buildings that have surplus internal heat from equipment or electronic gear.
Pros• Evaporative cooling• Small droplet size• Very large capacity• Can be put directly in space• Long nozzle life• Low maintenance• Fully modulating
Cons• Requires high inlet temp• Long absorption distance• Wetting of duct/standing water• Potential for bacteria growth• Particulate deposits/dust• Pure water preferred• Air compressor cost/kWh cost
Air/Water Fogger Humidifiers
Pros• No air compressor
Cons• Large droplet size• Very long absorption distance• Short nozzle life• High maintenance• On/Off or staged control only
High Pressure Water Humidifiers
Pros• Compact size• Small water droplet size
Cons• High initial cost• Must have ultrapure water supply
Ultrasonic Humidifiers
Pros Very low power consumption Potable or pure water Low initial cost Cleanable, low maintenance No standing water in duct
Cons Duct pressure drop On/Off or staged control Not good for close
humidity control
Evaporative Media Humidifiers