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Electric Superheated Rapid Steam Generator -  Comparisons with Pressure Boilers



Steam Generator Comparisons with Pressure Boiler/Autoclave
OAB® Models Full Poducts Display Information Request

Feature One Atmosphere OAB® Steam Water Tube Steam Boilers (wood or gas heated) Electric High Pressure Steam Boilers
Maximum Steam Temperature1

A 300-1300°C is Standard.   Choice of Models.

High Steam Flow Rate.

Sometimes up to 600°C with special Economizer and Superheater.  Without is about up to 134C for 3 Bar. 134°C for 3 bar steam.
How much water content in steam on start up? Negligible High water content Most often high water content
Delivery Time:  Compare the OAB® or HGA  initial time to start up at the user location anywhere in the world. Models are easily installed in a day and there is no anticipated wait for steam certifications prior to start-up of steam generation. Unknown.  Generally certifications may be required.5 Small units could be plug and play.  Large units may require certification time.5
Real Efficiency (Cold Water to Superheated Steam) >96% <85-90% ~85-95%
Idling Time/Energy Waste - when not in use Low wastage (Choice of Continuos or On-Off steady-state steam) High Moderate

Start Up Time(2) 

Non Steam Producing Energy Usage Time

Nearly Instant 60+ Minutes. Becomes slower with higher pressures and volume requirements ~60 Minutes. Becomes slower with higher pressures and volumes. (Not including cool down and pressure release for autoclaves)
Suggested Inlet Temperature3 The available tap Temperature or Water resrvoir temperature.. Room Temperature. 40-60°F 20-35°C
Capital Cost per Kg of Steam3 Low.  Financing available when qualified. High Moderate. Depends on temperature/pressure required.
Operational Costs4 Low even up to 1300°C. High Low-Moderate
Unit Footprint Small and remotely locatable power panels.  Starting at 1 'x 1'x 1'.  Large Depends on size and pressure requirements.
Plug & Play Operations Yes.  Easy manual supplied. No No
Requires Boiler Certifications5 No Yes Yes

Low for OAB and HGA (Unit can be used for continuous production of steam).  On account of the low foot print and modular designs the MHI-Never-Down Service™ is available for all steam units as applicable.

Low-Moderate Low

Utilizes Combustion7

(Requires Ventilation)

No Yes No
Energy Needed to produce 100 Kg/hr steam from cold start ~100 kWh @~350°C.  Water at Room Temperature to Steam. ~150-200 kWh Equivalent (Including start up time consumption).  Not always reported from room temperature water. ~150kWh Equivalent (Including start up time consumption). Not always reported from room temperature water.
Power Weight [Kg Equipment/(Kg/hr) of steam] for a 100kW Generator ~2 Kg per Kg/hr of steam. ~5 Kg per Kg/hr of steam (Weight increases with temperature/pressure) -
Maximum Work Potential (Based on second law limitation)  Base is 1 Bar 100C liquid water for all.

672 kJ/Kg for 500°C superheated steam

1973 kJ/Kg for 1300°C superheated steam

755 kJ/Kg for 10 Bar saturated steam

1169 kJ/Kg at 100 Bar saturated steam

Generally not used for creating work.
Enthalpy (heat) Content 3489 kJ/Kg for 500°C superheated steam at 1 Bar

2777 kJ/Kg for 10 Bar saturated steam

Saturation steam temperature 180°C

2725 kJ/Kg for 3 Bar saturated steam

Saturation steam temperature 134°C

Running at Partial Capacity With MHI Electronic Controls, No loss of efficiency

Significantly lower efficiencies, if model is capable

Lower efficiencies

Air Contamination Effects

Extremely high operation temperatures diminish effects of air

Air contamination harms output

No air contamination is allowed (strict)

Piping Losses Discrete, locatable units reduce necessary piping. The one atmosphere pipe can be better insulated and lighter. High pipeline pressure combined with long piping distances leads to heat loss and dangerous conditions in the event of pipe failure.  Pipes can be heavy. High pipeline pressure combined with long piping distances leads to heat loss and dangerous conditions in the event of pipe failure.  Pipes can be heavy.
How far can I run my pipe?  Infographic. OAB is better than a boiler OAB is better than a boiler OAB is better than a boiler
Typical Improved Multiplier Efficiencies for down line processes (Energy) Application dependent -  sometimes over 50% - -
Improved Water Efficiency Multiplier Application dependent -  sometimes over 50% - -
Request OAB Quote

1Maximum Steam Temperature obtained from production models; includes the use of superheaters.
2Time from a cold start to reach maximum operating temperature.
3Capital Cost per Kg of Steam calculated by dividing device output by device cost. Similar magnitude output devices are used. Prices used in calculations are general estimates obtained from public sources.
4Operational Cost per Kg of Steam calculated by dividing output by resources consumed, excluding water. Resources assume prices of $0.09/Kwh and $5/1000 Cu Ft for Natural Gas.
5Boilers using high pressure vessels may require annual inspections and certification certificates especially when over 1 bar gauge. Pressure certificates, ASME and local government regulations however vary considerably and could change so please confirm with local authorities.  Please click here to review some of the codes posted on the web.  Steam generators that operate at One Atmosphere may not need certifications.
6Most boilers require routine cleaning and inspections that impact uptime.
7Combustion by products include NOx and other harmful gasses. Combustion restricts applications of many steam boilers.  Almost always, flame and pressure certifications codes if applicable are related to safety.

Why use the OAB®


Real Cost of Project:  Gas boilers are not a quick start and shut down operation.  If you use a gas fired boiler say 72 KW units perhaps it is enough but one has to add several hours of boiler running time to understand the efficiency- unlike the OAB® steam generators.    Please add additional monitoring and labor time.  Also add inspection time and pressure fittings/lines that could be required with any conventional boiler. For gas fired or other combustion type boilers one needs a separate set up and construction management crew and installation crew.  Boilers can be dangerous -  there are many instances where boilers an autoclaves may have exploded (blown-up) e.g. recent report.


Clean: For each kWh of electricity generated by fossil fuel fired power stations about 0.45kg of carbon dioxide is produced. Burning fuel will produce CO2 in a gas or fuel fired boiler.  For the electric boiler there may have been CO2 produced at the power plant.  Big plants have more efficient cleaning possibilities.  Please vent carefully if burning fuel.


Traditional boilers yield saturated steam (Tsat and Psat are linked).   Boiler efficiencies increase with lower pressures. At 10 Bar the saturation temperature (Tsat~180C) which is much lower than the basic OAB output temperature and the efficiency is a lot lower than OAB steam.  High temperatures can almost instantly be achieved with the OAB and other MHI steam generators at a safer 1 bar pressure.  Regardless please take all precautions e.g. that include high quality safety glasses, non-porous insulated clothing, high temperature non-porous gloves, proper boots and all other safety equipment when in the presence of steam generators.


If the steam is for heating purposes, please compare the enthalpy.  If the steam is for work purposes please use the work potential row below, the work potential increases with both temperature and pressure.  Work potential is measured from 25°C base temperature.  The cost of boilers increases for very high pressure ratings.  However even at 100 Bars the  saturation temperature is only 311°C.  Again a fairly easy and routine temperature from the OAB steam generator.

1 Bar =100000 Pa = 14.5 psi

10 Bar =1000000 Pa =145 psi

100 Bar = 107 Pa = 1450.3 psi

Steam Tables

Pounds of CO2 emitted per million BTU of energy for various fuels: 

Coal (bituminous) ~206
Diesel fuel or heating oil ~161
Gasoline (common) ~157
Propane ~139
Natural gas ~117

Steam Models

OAB® Models Information Request

Industrial Steam Generation Systems 1Kg/hr - 108 Kg/hr

Pure Steam Generator High Steam Flow Steam Generators 1300C steam

OAB® Single Phase 1-12 kg/hr steam

OAB-36® Scalable Systems 36-108 kg/hr

HGA-S-CX-1300 Systems

Laboratory Scale Steam Generation Systems



HGA-S   and HGA-S-P Models



Superheated Steam Generators Applications


The kg/hr is nominal steam production rate.  Temperature and production rate are setting dependent.

350 Models expected to produce steam temperature in the range of 300-380°C

550 Models expected to produce steam temperature in the range of 500-700°C

750 Models expected to produce steam temperature in the range of 700-900°C


The output for the clean steam is easy to fit.  Sealant is provided for the user when attaching tubing for steam travel beyond the exit.  Vittori tubes which are insulated flexible tubing with connectors are also available from MHI.  Please Contact to request additional information.

Water Flow
Typical 1.5" NPT Outlet Nozzle
  Easy to attach to all pipes.

Assortment shown below.

OAB steam outlet easy to attach to MHI steam pipe
MHI steam pipe

All control systems are industry tested.  Easy to Install and Use.

Single Phase 220/240V (XPAN) or Three Phase  (TRIPAN) for Common World-wide Voltages

Steam Applications


OAB® Models Information Request

How much money savings from energy savings with smart steam power technology

Lower power consumption by :




Approximate savings per year of :




Assumptions include 1kWhr-10 US cents.  Continuous use for the year.

Consumer Packaged Goods Industry

Rapid Packaging With Energy Benefits
Easy steam tuneel for several uses

~90% energy and water conservation, even for the most complex-shape glass bottles.

Bring your designs to life with beautiful colors and creative shapes


Antimicrobial Steam
Portable steam generator. 

Cleanliness at several levels


One Atmosphere Boiler OAB® Other Suggested Applications

Why use an autoclave if your need is high temperature steam?   

Calculate the energy used in pressurization/vacuum and compare foot-print with the OAB. 

Foot print of steam generators.  Boilers are not for continuous steam Save wasted energy from vacuuum or pressure

Commonly Asked Question: Does one need high pressures or vacuum for steam to penetrate textiles or cloth packs?

Answer:  Most often no provided the steam is superheated properly. Steam self-propels as a gas. Unlimted capacity for continuous steam generators.

For a more detailed answer......please inquire here for pack penetration.

Calculations of Savings from Smart Lower Power Consumption Technologies

Efficient steam tunnels for packaging, shrink wrap, antimicrobial and textile

Use the OAB® for Oil Softening of Heavy Oil in Wells and Tanks.  Transition towards smart capital expenditure (CAPEX) and innovative operational expenditure (OPEX) are imminent in the oil and gas industry, especially with highly unstable barrel prices. Reduce foot print.  Easy to carry.  Reduced use of electric and water.  Use for Oil Mud.  Most Compact.  OAB 4 is about one foot by 1".

Pilot Plant Steam Generator for Possible Pharmaceutical Applications.  Remember price of energy is almost the same for one unit of energy (gas or electric) but electrical devices can be very efficient, better controllable and often much cleaner.

Simple SaniZAP Clean dirt and grime in difficult to reach places.  First soften and clean with handheld superheated steam then powerblow with hot air.  

Need more steam - the OAB models are ideal. Steam-soften with the proper superheated MightySteam.  Then VTA hot air blow with the powerful VTA-1GC  hot air powerblower unit.  Simple.  No water mess and use of the highest temperature steam.


Pilot Plant Steam Generator for Possible Pharmaceutical Applications.  Remember price of energy is almost the same for one unit of energy (gas or electric) but electrical devices can be very efficient, better controllable and often much cleaner.

Electric Steam Generator. Foam cutting high speed, low power, no mess with thermal steam cutter.  Use best steam that evaporates on cutting.  Ultra High Purity Steam. Also called UHP or UHT steam.  Textile, continuous heat setting and laundry steam chamber use.

Superheated Steam Generator for use in steam oxidation studies.  Use HGA-S or HGA-M.

Continuous steam.  Unlimited capacity.

Save big on easy paint removal techniques with MHI steam from enamels to hard paints  (view powerpoint  -   inquire or rapid buy).  Can you find a better paint remover?   Foam cutting.  Thick foam cutting speeds ~1"/s.

Save 90% energy for cleaning (example for bird droppings).  Consumer packaging labels.  Improved energy, less water use, improved speed and quality.

Energy Saved for Laundry or Garment pressing.  Car seat Pressing.  Laundry Use.  The energy requirement is approximately 0.15 – 0.30 kWh / kg of linen (source This is a good number for dry-cleaning but for full steam drying it may be best to use a number like ~1kWh per /kg.    If you are using and paying operationally for a 300kW boiler (1,024,327 BTU/hr) (or 30BP); are you dry-cleaning 900 kg (close to a ton of linen) of laundry in an hour? If this is not so please consider OAB instead to save energy. The cost of energy is similar whether gas or electric. Click here for savings from energy efficiency.  Garment dewrinkle, heat-setting and textile conditioning in a rapid energy efficient manner.

 Energy saver for heat set of textiles (dye drying).  Choose OAB-4-300 Model.



Seats pressing in rapid demand operations like automobile seats manufacture.  At 10 cents per kWh a 300 kW boiler operational cost could be as high as $30 an hour.  A 10 kW OAB machine reduces this payment to ~ $1 per hour.  Many electric companies offer grants to make capital changes with energy efficient new machinery.  Whether a 12 kW OAB may substitute for a 300 kW boiler depends on the application.  Most applications where a high velocity jet is required can be met by the OAB.  Please see video in Videos and Media Gallery section.

Drying with steam- ceramics to textiles.  Choose steam higher than 250C.  Non condensing. Note OAB steam generators may be turned off and on quickly unlike most pressure vessel type boilers. Continuous steam without pressure drop again best for quality control.  Most often neither pressure or vacuum is required in an applications.  Pressure is often just a way for traditional boilers to achieve high temperature-  not required for the specific application.  See also Steam Energy Calculator and steam kinetics.  Drying of silicates, sand, porcelain and investment molds during casting.


Steam Copper-tubes for water delivery to start protective oxide (Malakite) barrier in them.  Reduces copper contamination and other contaminants from pipes.  Do internal pipes. Please contact MHI for known technical results.  User may need to call government agency for results. 

Please contact MHI for details.

High Pressure Steam Boiler can be avoided. Laundry boilers, tunnels and other energy improvement uses are possible in the garment and laundry industry. Several levels of efficient cleaning and de-wrinkling Higher temperatures de-wrinkle leather more easily. E.g. Clean fifty pound loads with an OAB® and canopy. The canopy does not need to be a heat dissipating rigid surface!

Choose your own steam Bluing/Blackening for attractive surfacing.  Use steam generator for steam oxidation studies. 

Use Process Steam for oil (normal and heavy oil) and natural gas to reduce viscosity.

Commercial Steam Boiler and OAB. Cheese Making

"Heat Processing to make cheese is varied in practice. The time and temperature programme for heating is determined by the method of heating and the type of cheese. Some cheeses require heating to temperatures above 40°C-56°C (133°F) Normally at 37 – 38°C the activity of the mesophilic lactic acid bacteria is retarded.  Time is taken check the acidity, Above 44°C or more the mesophilic bacteria are deactivated, and they are killed if held at 52°C between 10 and 20 minutes. Heating beyond 44°C is typically called scalding. Some types of cheese, such as Emmenthal, Gruyère, Parmesan and Grana, are scalded at temperatures as high as 56°C (133°F) . Some of the most heat-resistant lactic-acid-producing bacteria survive this treatment e.g. Propionibacterium freudenreichii ssp. shermanii". Credit to is acknowledged for the above information.

Pure Steam Generator.  Milk and Cottage Cheese.  Augmentation of process.  Significant reduction of energy from unwieldy and high Btu/hr (kW) boilers currently see use. 

A frequently asked question is:  I do understand that milk products have increased considerable resistance to deterioration when UHT steam is used.  However will this denature protein in any way that is bad for me?  The answer can be found on many web sites like   Bakery Operation with on demand (on-off) steam.  Food processing humidification. Benefits that may also follow from SW-OAB® Steam in addition to saving considerable energy for shrink labeling activities. — OAB® and MightySteam®'s patented heating system 
and service allows for an industrial strength steam output.


Superheated Process Steam for Odor Removal

Electric Superheated Steam

What is the difference between Disinfection and Sterilization?   See adjacent box.
Steam Sanitation: Studies have shown that even 1 second of residency time of 248°F (120°C) steam is roughly 97% effective against common strains of bacteria1. In controlled experiments, higher temperature steam requires lower residency times to achieve effectiveness. This result most likely follows the common law of chemical kinetics where speed increases exponentially with temperature.

What is the difference between Disinfection, Sanitizing and Sterilization?  Sterilization vs. Disinfection vs. Sanitization
There are 3 fairly commonly accepted levels of "clean" in many industries. Sterilization refers to the statistical destruction and removal of all living organisms. Disinfection generally refers to inanimate objects and all vegetative cells, but not spores. Sanitization refers to the reduction of microorganisms to levels considered safe from a public health viewpoint. The official definition of sanitization, according to the Association of Official Analytical Chemists, for food product contact surfaces is a 99.999% (5-log) reduction of contaminants in a 30 second period. For non-product contact surfaces, a 99.9% (3-log) reduction in contamination is necessary. What is anti-microbial cleaning?

Steam Boiler for Steam Kettles, Processing Mash with Steam, Saving Energy and Materials.  Save considerable energy and time.  Generally from cold start cut up to 1/3 the time.  Will preservatives be reduced by steaming - most likely not?  Problems with autoclaves

Commercial Steam Generator for packaging

View efficient steam tunnels for packaging, shrink wrap, antimicrobial and textile

Industrial Steam Generator and Tunnel for cotton fiber moisture doubling.  Moisture in cotton yarn fiber is able to make the fibre more abrasion resistant as well as more fatigue resistant.  Use for heat-set and save considerable energy.  No need to use vacuum or pressure chambers. Review amazing ROI.

Tankless Instant Steam Generator

Endotoxin Free Steam

Industrial Steam Boiler

Laboratory Superheated Steam

Low Pressure Steam Boilers

Electric Superheated Steam Generator

High Pressure Steam Boilers

High Temperature Steam

Request For Quote

Article on HGA output for steam and superheated steam.

Read an article on "Drying with steam or drying with air - a case study for clay, wood, food processing, etc".

Low Pressure Steam

What are the pressures in healt care to convert to superheated non pressurized open steam: Water quality in steam sterilization and hospital boiler systems could be a problem and can be a factor in leading to rust and corrosion of surgical instruments.  Hospitals may not know how much it costs them to steam sterilize, yet they know it is expensive.  Creating pressure uses energy.  Main drivers are convenience of not having to be connected to boiler, safety and efficacy



Low Pressure Steam Boiler

Steam Generator Boiler

Steam Roasting.  Activated carbon by steam both Stage 1 and Stage 2 (Steam of 700C and 1100C)

Electric Steam Boiler

Electric Steam Superheater

Steam Boilers

Steam Reforming Hydrogen

Wine barrel conditioning and reconditioning.   See also hybrid.

Heavy Oil recovery with low energy and water input.

Use in Oil storage and Oil tanker applications.

Wood Conditioning for utility, packaging and hobby use.

Safe kettle-heating for Breweries, Flavors and other such use Industries. 

Energy efficient kettle heating for Breweries, Flavors and other such uses.

Superheated Steam Drying

Instant Steam Generator

Superheated Steam Boiler

Touch-up steam MS400-01 - 1Kg/hr of steam up to 400°C. Use for steam spray purposes only. 
Request OAB Information

Traditional boilers yield saturated steam (Tsat and Psat are linked). Boiler efficiencies increase with lower pressures. At 10 Bar the saturation temperature is only 180°C.   This temperature can almost instantly be achieved with the OAB and other MHI steam generators at a safer 1 bar pressure.


If the steam is for heating purposes, please compare the enthalpy.  If the steam is for work purposes please use the work potential row below, the work potential increases with both temperature and pressure.  Work potential is measured from 25°C base temperature.  The cost of boilers increases for very high pressure ratings.  However even at 100 Bars the  saturation temperature is only 311°C.  Again a fairly easy and routine temperature from the OAB.

1 Bar =100000 Pa = 14.5 psi

10 Bar =1000000 Pa =145 psi

100 Bar = 107 Pa = 1450.3 psi

Media Gallery

Disinfection Studies, Videos, Biomass, Antimicrobial possibilities, Oxidation, Fiber Conditioning, Textiles Cutting Nozzles and mess, low power, full quality steam and high speed use for from cutting to shrinkwrap.  Contact us for more information.  OAB® Models and MightSteam Models Information Request

Steam-jet cleaning of glassware such as glass-vials with 550°C superheated high quality steam. Results from are only guidelines for biofilm elimination- please verify directly.

Please link to video if your browser does not support the video.
Ohio State Presentation
Paint Removal Presentation

MHI's One Atmosphere Boiler superheated steam boiler features patented InstaSteamâ„¢ technology, allowing for rapid startup times, unparalleled efficiencies and up to 1300°C temperatures. BoilerFreeâ„¢ technology allows most OAB units to be installed without the need for traditional boiler certifications. The OAB® is ideal for use as an industrial steam generator, for dewrinkling operations, heating of vats, cpg bottle labels, cleaning at several levels, superheated steam drying and dozens of other specific applications requiring a high efficiency boiler that does not require standard boiler certifications. Use to replace boilers with better efficiency or to augment steam applications.

Pure Steam. Clean Steam. One Atmosphere Boilers generate superheated steam that is free of contaminants. The OAB's steam is ideal for pharmaceutical, cosmetics and other industries requiring the highest quality steam. OAB steam is also suitable for use as utility steam in many applications due to its high energy content. Steam is a very powerful non-toxic agent but adequate safet care must be taken when using hot steam. Periodic treatment with high temperature steam is recommended (when used properly) to achieve maximum benefits. Steam quality can sometimes be checked with the proper steam chemical indicators. For bacterial testing please check with a professional microbiologist.

Highly Scalable. OAB units can produce from 1kg/hr to over 1000kg/hr. Modular design allows for easy upgrades and utilizing the unit where it is needed, all without routing steam or venting pipes. MHI is well known for Smaret heating devices.

Compare Efficiency. Three types of efficiencies are important to consider. (1)the efficiency of the steam generation device where the OAB® and MightySteam® excel; (2)the efficiency of the downstream process that the steam is used for; and (3) the overall water usage efficiency and propensity to recycle the water. The one atmosphere steam-gas generator/boiler performs well in all three categories.

How does one increase the rate of production?

  • Short Answer: Increase the temperature of the process gas or steam.

  • Long Answer: Please click to Steam Calculator page.

Better conversion factors allow OAB units to use less resources to produce more steam. A standard OAB steam output at 350°C, is almost at the theoretical efficiency of power conversion for the OAB steam generation! The OAB's rapid start-up (generally with a minute from cold start) also adds considerably to the overall lowering of energy usage.

Getting to temperature quickly and faster results in lower operational wear and related costs i.e. an overall higher productivity with corresponding higher kinetics. The output velocity of the 550°C OAB steam is very high - almost 40m/s or more. This feature is used for the uniform heating of kettles/heat exchangers and for reaching large piping distances without significant loss of temperature. For industrial vats and kettles, the heating rate makes a considerable difference to the overall process economics. A general rule of thumb of productivity from traditional pressure boilers is - (0.35 Gallons of heated product like water)/kWhr (energy). For the OAB it is closer to - (1 Gallon/kWhr) i.e. almost three times (numbers may be lower or higher as they are situational dependent and one needs to evaluate on a case by case basis).


Request OAB Quote

Industrial Steam Generation Systems

Pure Steam Generator High Temperature Steam 36 and more Kg/hr 1300C steam

OAB® Single Phase.  Smart Steam Technology.

OAB-36® Scalable Systems

HGA-S-CX-1300 Systems

Steam Generation Systems (1 or 2 Kg/hr steam and 110/220V) and Superheater Systems

MHI Superheater/Supercharger


HGA-S   and HGA-S-P Models

SaniZap-1 and MS-400 Technology


OAB Models are available with single-phase and three-phase controls. Easy to Install. Turn on-off as required. 


Do Temperature and Pressure Impact a Steam Reaction?

OAB® Compared to Traditional Boilers

Steam Calculator, Productivity Enhancement and FAQ's

|Physical Properties of Moist Air/Gas |

What are Steam and Humidity?

The OAB offers a scalable design and because of the small foot-print qualifies for the MHI Never-Down policy. The scalable design allows the user to choose what fraction of the boiler needs to be turned on on a given day or hour and changed at will. MHI electronics provide full data logging, on-screen data acquisition display and a repertoire of 100 programs - all in the small sophisticated control panel.

MightySteam® is a Registered Trademark.

OAB® is a Registered Trademark.

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©Micropyretics Heaters International Inc. 1995 - 2019
750 Redna Terrace Cincinnati, OH 45215, USA
Telephone: 513-772-0404 | Fax: 513-672-3333