Potable water heat exchanger

This indirectly heated potable water tank makes available an appliance meeting all the requirements for safe potable water and gives the consumer a device with a high continuous output of hot water, even when demand is high. The improved device contains the following improvements: PA1 (1) vented double sided metal sheet heat exchangers which result in a significant increase in the temperature of the water, PA1 (2) vented heat exhanger tubes as a further means to heat the water, PA1 (3) a corrugated metal heat exhange sheet in the vent space to transfer heat through its surface to the water, and PA1 (4) a vented potable water temporary storage reservoir where the heated reservoir walls additionally heat the stored water. The properties of the sheet heat exchangers result in a very large inner and outer areas of heat exchange in contact with the water to be heated and the heating fluid and in a narrow inner flow space heating surface and large heat exchanger plates which results in the highest heat extraction from the externally heated water.

TECHNICAL FIELD 
My invention relates to heating potable consumption water by an indirect 
means, with a storage tank to temporarily store the hot water until it is 
drawn off the reservoir by the consumer. 
This invention will ensures that a constant supply of hot water is 
available to the consumer by providing the means of large heat exchanger 
surfaces, heating the water before it enters and exits the said reservoir, 
where it receives additional heating from the storage tank walls. 
BACKGROUND ART 
Prior to this invention the output flow from vented indirectly heated 
potable water tanks was very limited and required a long time to reheat 
the replaced used water. 
DISCLOSURE OF INVENTION 
The invention is to provide large heat exchanger surfaces to heat the 
potable water before it enters and exits the storage tank reservoir by 
using input and output heat exchangers, and further heating the stored 
stored water with the reservoir tank walls. 
The heat exchange is provided by the means of a vented double sided metal 
sheet heat exchanger, exchangers or vented pipes, pipes or any combination 
thereto, providing a high constant flow of hot water to the consumer and a 
short reheating time if the water demand has been very excessive. 
The efficiency of the heating methods, removes the need for any other 
installed heating make up devices.

DESCRIPTION AND PREFERRED EMBODIMENTS 
The invention is further explained with reference to the embodiments and 
shown in the accompanying drawings: 
Referring to the plan view of FIG. 1, the illustration comprises of three 
tanks with the innermost potable water reservoir tank 4 wherein this tank 
temporarily stores the water and provides additional heat to the potable 
water with the heated tank walls. 
The reservoir tank is surrounded by a vent space tank 10 providing the 
means of a safety air gap to separate the fluids contained in the 
reservoir tank and the boiler water 7. 
The outer boiler water tank 12 surrounds the vent space tank and contains 
externally heated boiler water providing the sole means to heat the 
potable water in the reservoir tank, heat exchangers, pipes and tubes. The 
said tanks are of any shape or size and disposed on any axis. 
The air space vent tank 10 hereinafter referred to as the vent tank 
requires a means to overcome the insulating effect of the air gap 11 and 
still retain the safety air space. This is achieved by the insertion of 
the heat exchange elements 14, shown here as a metal heat exchanger sheet 
16, into the vent tank between the adjacent tank walls. As shown a metal 
heat exchanger sheet is comprised of elements which are fully illustrated 
in FIG. 3 and in FIGS. 12a and 12b. The sheet is in flush contact with the 
adjacent tank walls, providing the means for maximum heat transfer between 
fluids by conduction of heat though the said heat exchanger. 
The metal heat exchanger sheet can be in other configurations. 
Illustrated in FIG. 1 is the input metal sheet heat exchanger 3 which has a 
high heat transfer to the potable water flowing through the heat 
exchanger, the flow space 20 is narrow as indicated in a clearer manner by 
referring to FIG. 5. 
This flow space results in maximum heat transfer for the cold water as we 
have a small volume of water flowing over large heat transfer surfaces 18. 
The metal sheet heat exchanger immersed in the boiler water is spirally 
disposed so that a maximum length is contained within said water tank, a 
double sided heat transfer surface is show by 18 of FIGS. 4 and 5, wherein 
the heat exchange sheet elements being indicated by 14, of FIG. 4, and the 
partial cross section of FIG. 5. 
The input heat exchanger can be disposed on any axis and in any 
configuration. 
The input and outlet of the boiler water tank 8 and 9 of FIG. 1 use the 
means of pipes to distribute and collect the boiler water in the tank by 
the pipes indicated as 15. With the same means used to distribute the 
water in the heat exchanger sheets, all the pipes have sealed ends with 
entry and exit water flow holes along the length, the pipes are shown as 
21 and 22 of FIG. 4. 
The pipes can be in any configuration and disposed on any axis. 
Shown in FIG. 8 is the reservoir tank drain tube 25 and vent tank drain 
pipe 26. 
Encasing the outer boiler water tank 12 is a insulated coating 13 to 
minimize atmospheric heat loss. 
The water flow and the heating function, commences at the supply input pipe 
1 of FIG. 1, where the cold supply waters enters the supply pipe and into 
the input metal sheet heat exchanger 3 of FIG. 8. 
The input heat exchanger causes a significant increases of the temperature 
of the supply water before it flows into the storage reservoir 10 where it 
is additionally heated by the reservoir tank walls. 
When the hot water is drawn off by the user, the water exits the reservoir 
tank to the building plumbing through outlet pipe 6. 
The externally heated boiler water 7 enters the outer tank through inlet 
pipe 8 exiting the said tank when it requires reheating through outlet 
pipe 9. 
The boiler water is the sole heating source for the potable water requiring 
the boiler water is kept at a temperature between 180 to 190 degrees 
Fahrenheit. 
Indirectly heated potable water storage tanks are controlled by codes to 
protect the consumers health, one requirement is that an air space must 
separate the fluids so that any deterioration of the walls that separate 
the fluids cannot cause cross contaminate the potable water, said air 
space is referred to as the vent space and shown as 11 in FIGS. 1, 2, 3, 
5, 8, 9, 10, and 11. The reference number 30 indicates the areas where 
vent spaces are mated into vent space as shown in FIGS. 7 and 7a. 
The air space vents are indicated by 11 of FIG. 2, FIG. 3, FIG. 5, and the 
vent tank 10 enclosing the metal heat exchanger sheet 16. 
The partial cross section of the vented input heat exchanger sheet FIG. 5, 
is further explained, wherein both outside plates, 18, of the said sheet 
are immersed in the boiler water. 
One of the advantages is providing the means to double the area of surface 
contact with the boiler water for a given length of heat exchanger. 
With the narrow potable water flow space shown by 20 a small volume of 
water is in contact with the internal surface plates 19 and the heat 
transfer elements 14 have minimum width so that the outer plates 18 are as 
close as possible to the inner potable water flow plates 20 maximizing 
heat transfer between the fluids. 
The vented sheet heat exchangers of FIG. 6 or vented pipe heat exchangers 
23 or 24 of FIG. 8 and FIG. 15 can be configured in any shape and disposed 
on any axis. 
This invention is not restricted to having a reservoir tank and input and 
output heat exchangers. It may suffice for the heat exchangers to be the 
only means of heating if an high initial hot water flow is not needed. If 
air space venting is not a requirement for supplying the hot water, then 
the device may be non-vented indirectly heated water tanks. 
In FIG. 15 the combination of heat exchanger sheet 3 with pipe heat 
exchangers 23 or 24 either can be used as input or output heat exchangers 
to suit requirements. 
Hereinafter the illustrations shown in FIG. 16 and FIG. 17 are flow chart 
drawings to describe the installations where the indirectly heated water 
tank may be used, and now the elements are identified by alphabetical 
lettering. 
The description of FIG. 16 shows the flow of heated water from heater H 
where the flow follows the arrows as indicated, flowing through the zone 
valve J. The zone valve will only allow water to flow if the water in the 
outer tank C requires reheating. The boiler water C returns to H through 
the circulator pump I with this cycle continuing to maintain the 
temperature of said water C. 
The building heaters are indicated by E. The heating can be controlled by 
zone valves which can provide different levels of heating to either branch 
of the building. 
The supply consumption water enters the appliance at B and exits to the 
consumers hot water at A. 
In FIG. 17, the hot water follows the path as described in FIG. 16, but the 
illustration shows the appliance tanks L, M, and K, connected in parallel 
with each tank provided with a water mixing valve indicated as P, Q, and R 
which controls the output heat or can be the means to provide water at 
different temperatures to other areas or locations. When used together, a 
greater cumulative hot water output flow rate can be obtained.