GAS GEYSERS

- Akshita Mehta

- S.Y.BHsc – A-3

- Roll No. - 65

INTRODUCTION

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.

TYPES OF GAS GEYSERS

The old standard: atmospherically vented tank “Power Vent” tanks: the new standard Energy Ratings for all types

THE OLD STANDARD: ATMOSPHERICALLY VENTED TANK

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.)

ATMOSPHERICALLY VENTED TANK

“POWER VENT” TANKS: THE NEW STANDARD

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

SUPER-EFFICIENT “CONDENSING” TANKS

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.

ANATOMY OF A GAS WATER HEATER

PARTS OF GAS GEYSERS