This document discusses different types of gas geysers, or water heaters. It begins by describing the traditional atmospherically vented tank, noting that less than 60% of fuel heat ends up heating water and there are safety issues if combustion gases backdraft. It then explains that the new standard is "power vent" tanks, which include a fan to reliably vent gases outside and allow for greater efficiency. The document also discusses "sealed combustion" heaters and super-efficient "condensing" tanks that can transfer over 90% of fuel heat to water.

1. GAS GEYSERS
Akshita Mehta
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S.Y.BHsc – A-3
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Roll No. - 65

2. 
Point of use water heaters and recirculating pumps save water and
energy by eliminating the wait for hot water when you need it.

They provide a fast, effective method for getting hot water
instantly to remote faucets and fixtures in your home or
business. By installing a point of use water heater right where it is
used or a recirculating pump that delivers a continuous loop of
hot water, you can have hot water instantly.
INTRODUCTION

3.  The
old standard: atmospherically vented tank
 “Power
Vent” tanks: the new standard
 Energy
Ratings for all types
TYPES OF GAS GEYSERS

4. Traditional tanks allow 20% or more of the fuel’s heat to waft away up the chimney. More is lost as
the hot water cools from air moving through the flue in the middle of the tank. All in all, less than 60%
of the fuel's heat typically ends up as hot water. Second, and perhaps more important, is the
possible safety issue of backdrafting flue gasses. As with older atmospherically vented furnaces (see
Three Kinds of Gas Furnaces for your Remodeling Project), the only force that lifts the burned gas
exhaust up the flue is the buoyancy of leftover heat in the gasses. This force is not that strong, and if
anything goes wrong, the combustion byproducts can accidentally enter the home instead of going
up the flue. These combustion gasses are never safe, and can even be deadly if significant carbon
monoxide is present. (A carbon monoxide detector is recommended by the Building Performance
Institute for any home with gas-burning
appliances.)
THE OLD STANDARD:
ATMOSPHERICALLY VENTED TANK

5. ATMOSPHERICALLY VENTED TANK

6. In our work as design build remodeling contractors, most of the heaters we have installed lately are
tanks that
overcome the problems with those old-fashioned, atmospherically-vented heaters. The simplest
upgrade is a “power vented” tank. These have a fan that pulls the combustion gas out of the tank
and pushes it through a plastic vent pipe to the outdoors. The fan setup reliably removes the flue
gasses from the house, preventing the possible health and safety problems with natural draft heaters.
In the older heaters, a lot of heat has to be left in the flue gas so it will rise up the chimney. With the
fan pushing the flue gas, more efficiency is possible because more of the heat can be left in the water
instead.
“Sealed combustion” heaters are similar, with the same fan and flue gas pipe, but they additionally
include an inlet pipe that brings outdoor air into the combustion chamber. That saves your
conditioned air from being removed to the outside. While power-vented tanks themselves cost more
than an atmospheric-vented unit, the installed cost in a new construction situation is often lower. The
plastic flue can run out a sidewall, and is inexpensive compared to the vertical metal flue (and
framed-out chase through all floors above) that are needed for an atmospheric-vented heater.
“POWER VENT” TANKS: THE NEW
STANDARD

7. “POWER VENT” TANKS: THE NEW
STANDARD

8. A couple of relatively new types of heaters take this sealed combustion concept
further, with super-efficient heat exchangers that take even more of the heat out of the
flue gasses, saving more on fuel costs. I’d separate these into two categories: stainless
steel tanks with efficient exchangers, and a conventional steel version. The stainless
versions have been around a while. Polaris and Phoenix are the two brand names I’m
aware of. For the true long term thinker, these are possibly the lowest long-term cost
units, because the stainless steel tanks should outlast us, our children, and possibly our
children’s children! These tanks have a super-efficient modulating burner and a high
efficiency exchanger that transfers over 90% of the heat value from the gas, much higher
than standard tanks.
SUPER-EFFICIENT “CONDENSING”
TANKS

9. ANATOMY OF A GAS WATER HEATER

10. PARTS OF GAS
GEYSERS