Patent Application
20070108307
The present invention relates to systems for the heating and cooling of buildings, reduction in capital expense, and the distribution of water for minimizing the number of piping risers and avoiding over-pressure supplies through the strategic placement of pressure reducing valves.
Heating and cooling systems for multi-story buildings typically use specifically supplied and circulated hot and cold water for delivery to heat exchangers. Traditionally, room-by-room heating, and air conditioning systems in large buildings have been, what are known in the art, as four-pipe fan-coil systems; two pipes for chilled water flow, and two pipes for heated water flow. Individual fan-coil units placed at various locations throughout the building provide for zonal temperature control. Heating or cooling is provided by having the fan circulate air over a coil that is accessing either the hot or the chilled-water piping system, respectively. Water distribution systems for multi-story buildings also typically comprise various arrangements of water supply and returns.
Conventional 8 floor zones extend risers up through all suites with the associated water noise for the lower suites and the large number of risers. Each riser is associated with fire blocking and challenges at bulkheads and cross-over floors.
To date, choices for heating and cooling commercial or multi-suite buildings have been limited and equipment such as fan coils are an expensive, but known, solution.
Multi-story buildings further introduce challenges including problems related to hydrostatic pressure variation from floor to floor. In a 24 storey building the pressure at the lowest floor may be about 130 psig so as to maintain 40 psig at the highest of the upper floors or roof where the hydraulic head is at its minimum. To supply a 72 storey building from a single water supply riser would result in pressures at the lowest floor at about 250 psi. However, it is unacceptable to apply 250 psi or even 130 psig water for domestic use. Higher pressure in a domestic hot water system will ensure return flow to the hot water boilers but such pressures are too high for domestic purposes.
There is a need for a reduction in redundant piping, elimination of noise in suites, lower capital cost and more efficient systems in the heating, cooling and distribution of domestic water in high rise buildings. Applicant addresses these shortcomings and incorporates further improvements to heating and cooling systems, some of which can be incorporated with domestic water distribution.
Applicant has provided a system which significantly reduces the piping needed to supply domestic hot and cold water to one or more units, residences or suites in high rise buildings, solves issues associated with the supply of water at pressures above desired domestic use pressures, and incorporates novel heating concepts for multi-residence buildings. The number of risers throughout can be reduced in number by more than an order of magnitude. Noise issues associated with flow in risers extending through each suite is eliminated.
Applicant has recognizes that use of domestic water system for heating and cooling using partitioning walls as radiant walls, enables heating and cooling of adjacent rooms and better utilizes existing domestic water systems for minimizing capital expenditures such as through the reduction or elimination of fan-coil or hydronic radiant panel devices.
The partitioning walls condition room temperatures by acting as a cold or hot radiant wall either using hot domestic water for heating, or using chilled domestic water for cooling, or alternating therebetween using thermostatic valves for circulating either the heated domestic water or chilled domestic water.
Applicant further recognized that several aspects of pressure control at lower floors provides significant advantages. Use of full pressure, variable over elevation, domestic cold and hot water systems and pressure reducing valves as required for domestic service only, eliminates floor to floor risers and remarkably reduces the numbers of piping runs. Pressure and flow control is maintained despite the number of floors in the building. No longer do domestic water pressure and plumbing fixture requirements limit the use of common risers at full pump pressure at full hydrostatic head. Further, the system has several solutions for ensuring hot water availability and avoiding stagnation which can occur in some domestic lines, contrary to public safety and contrary to plumbing regulations in some jurisdictions.
In one embodiment, the system has a domestic hot water supply riser and a hot water return riser. At each serviced floor, a domestic hot water distribution main extends from the hot water supply riser to each of one or more suites and returns to the hot water return riser. On each floor, typically lower floors, at which a riser pressure is higher than preferred service pressure for domestic plumbing fixtures, a pressure reducing valve is situated at least between the distribution main and domestic use fixtures in the suites for reducing the pressure of the cold and the hot water as required. Coupling of the heating systems directly off of the supply riser at full water pressure and to the hot water distribution main provides an effective piping system for circulation of hot water through heating systems and allows for return of hot water circulation to the heating system without a need for further pumping. Further, implementation of a substantially constant circulation of hot water through the hot water distribution main ensures hot water is available on demand. Additionally, when heating is not required, regular and periodic circulation through the hot water distribution main avoids stagnation of the domestic hot water supply.
As a result, applicant has determined that up to 70% can be saved on the fluid piping in a building and 20% on the cost of the entire mechanical system. Supply risers no longer run through suites, eliminating noise. Bulkheads and cross-over floors are no longer a concern for domestic water distribution. Water circulation is simplified without a need for auxiliary pumps to return spent water to heating and cooling systems. With reduced numbers of risers comes less wasted floor area for accommodating piping. Use of domestic hot water for heating, and as desired domestic cold water for cooling reduced capital cost by reducing or eliminating fan coils and other equipment.
In one broad aspect, a system for temperature conditioning multiple serviced floors of a high rise building is provided, each floor having one or more suites having interior and exterior walls and having plumbing fixtures being serviced with at least domestic hot water. Such a system comprises: providing at least a domestic hot water distribution main at a supply pressure at each serviced floor for servicing the suites. The domestic hot water distribution main provides domestic hot water to one or more suites on the floor. The domestic hot water is thermostatically controlled through radiant tubing installed in one or more radiant walls in a suite, of one or more suites, for heating the suite. For each floor at which the supply pressure of the domestic hot water is above a first pressure threshold, typically a suitable domestic service pressure, the water pressure of the hot water to the domestic use fixtures is reduced to about the first threshold pressure using one or more pressure reducing valves situated between the distribution main and the domestic use fixtures of each suite.
Preferably, the system further comprises a domestic cold water distribution main for each serviced floor at a supply pressure. In embodiments where cooling is not required, such as in moderate climates, and for each floor at which the supply pressure of the domestic cold water supply at each floor is above a second pressure threshold, typically the suitable domestic service pressure, the water pressure of the cold water is simply reduced at the before the distribution main. Where cooling using domestic cold water is employed as well for the radiant walls, one can maintain the domestic cold water distribution main at full pressure for radiant wall circulation and, as applied to the domestic hot water, reduce the water pressure of the cold water to the domestic use fixtures to the second threshold pressure using one or more pressure reducing valves situate between the full pressure cold water distribution main and the domestic use fixtures of each suite.
Preferably, a heating system or heater provides heated hot water to each domestic hot water distribution main, and a hot water return riser returns hot water from the distribution mains to the heater. Similarly, a cold water riser provides chilled cold water from a cooling system or chiller to each floor's distribution main, and a cold water return riser returns cold water from each distribution main to the chiller.
For heating and cooling using radiant walls, a pair of three-way valves are employed, a first three-way valve controls whether chilled or heated domestic water is circulated into the tubing in the radiant wall, and a second three-way valve controls whether the thermally spent water returning from the radiant wall is returned to the cold water return riser or the hot water return riser respectively.
Preferably the domestic hot water main is fit with a flow control valve to flow back to the return riser so as to provide a controlled, yet substantially constant flow of hot water for ensuring a substantially on-demand hot water response at the domestic use fixtures. Preferably the flow control valve is positioned between the distribution main after the last serviced suite, and a return main to the return riser. The radiant walls and other heating loops can be provided with thermostatically controlled valves having periodic dump features to avoid stagnation.
Typically radiant wall are provided on interior walls of a suite for bi-directional heating. More preferably, suites adjacent an exterior wall, and similarly adjacent utility or common areas such as stairwells, can be provided with additional radiant tubing installed in the floor such as adjacent the exterior wall. As necessary, walls between adjacent suites can be fit with radiant walls, but are arranged for unidirectional heating to the suite having the thermostatic control.
Generally, as shown in
While referred to as a “radiant” wall, which suggests radiant heat transfer, other aspects of the principles of heat transfer are also inherent and contemplated, such as conduction to the wall surface and convection therefrom. Further, radiant walls 20 can provide thermal control including either heating and cooling. While examples are provided in terms of a hot radiant wall 20, heated using domestic hot water DHW, temperature conditioning or thermal control using a radiant wall 20 can equally include cooling using a circulation of domestic cold water DCW. Temperature adjusted water, which is circulated through radiant walls 20 for temperature control, is generally termed herein as thermal water and more specifically as domestic cold water DCW or domestic hot water DHW.
With reference also to
Within a radiant wall 20, the thermal tubing 21 is positioned sufficiently offset within the wall 20 from either wall surface to avoid accidental punctures from screws and other fasteners.
An implementation of various embodiments in the context of a high rise building 30 is set forth in
With respect to the radiant walls 20, and in
In
Domestic hot water DHW and domestic cold water DCW are also typically provided at each floor of a multi-story building and are circulated to each suite 11.
The hot water supply riser HWS and hot water return riser HWR extend to each of the multiple services floors 33 and are fluidly connected to the hot water heating system 31. Water pressure of the domestic hot water DHW in the risers HWS,HWR varies with elevation due to the variation in hydrostatic head.
The heating system 31 is illustrated at the top floor but could be located at any elevation in fluid communication with the supply and return risers HWS,HWR.
Further, on very tall buildings, vertical zones of multiple floors can be provided with their own heater, hot water supply and return risers (not shown). The multiple serviced floors can be arranged in vertical zones, further comprising for each zone a booster pump which supplies water to the zonal hot and cold water risers to ensure a pressure exists therein which, at a highest floor of the zone is at least domestic service pressure, and at the lowest floor of the zone, is at or below a maximum booster system pressure.
Where cooling functions are desired, a cooling system 41 such as a heat pump or chiller is also provided for circulation of chilled domestic cold water DCW through a chilled water supply riser CWS to each floor 33. Domestic cold water returns to the cooling system 41 through a chiller water return riser CWR. The cooling system 41 is illustrated at the top floor but could be located at any elevation along the supply and return risers CWS,CWR. Water pressure of the domestic cold water in the risers CWS,CWR varies with elevation. The temperature of the chilled water is pre-determined to avoid condensation issues as is known to those skilled in the art.
With reference to
Characteristic of multi-story buildings 30, each successive higher floor 33 experiences a corresponding loss of hydrostatic head and water pressure. In order to provide water under sufficient domestic service pressure PD to more than one vertically arranged floor in the building, the hot water supply riser HWS is pressurized, at lowest of the lower floors 33b, to a pressure threshold PH, which is often greater than the desired domestic use pressure PD, so that a minimum domestic pressure PL can be maintained at a highest of the upper floors 33t. The pressure threshold PH at the lowest of the lower floors 33b, is typically at a pump pressure for delivering at least the minimum domestic pressure PL to the upper floors 33t.
Similarly, the cold water supply riser CWS also extends either up or down the building 30, and is subject to the same variation in hydrostatic head and will operate at substantially the same variable pressures. Accordingly, the lowest floors 33b are supplied at the greatest pressure with water pressure diminishing at higher elevations to the upper floors 33t which are supplied at the lowest pressure PL.
Domestic facilities or fixtures 42, such as toilets, sinks and laundry hook-ups have a maximum service pressure and preferably operate at domestic service pressures PD. The fixtures plumbed with domestic water will a preferred hot water threshold pressure and a cold water threshold pressure. Usually the threshold pressures for the DCW and DHC at the fixtures 42 is the same domestic service pressure PD. As shown in
The pressure of the domestic hot water DHW and domestic cold water DCW in the risers HWS,CWS at lower floors 33b can be higher that acceptable domestic service pressures PD. Accordingly, the cold water DCW and the hot water DHW for these lower floors 33b are pressure reduced at the fixtures 42. One or more hot water pressure reducing valve 43 are at least provided at each suite 11 for reducing the pressure of the hot water DHW directed to plumbing fixtures 42. The valve 43 is located between the hot water distribution main HWM, which circulates heating water at full riser pressure through radiant walls 20, and the fixtures 42, which are fed at reduced domestic service pressures PD.
Upper floors 33t do not require pressure reduction as the water pressure is already between the minimum pressure PL and a preferred domestic service pressure PD. Accordingly, the domestic plumbing fixtures 42 for upper floors 33t are directly plumbed to the distribution main HWM at the full pressure of the hot water supply riser HWS.
Further, in
As discussed in co-pending application Ser. No. 10/851,349, filed May 21, 2004 to Applicant, the entirety of which is incorporated herein by reference, and discussed in the context of the use of fan coils as the preferred heating and cooling equipment, improved efficiencies and comfort are achieved using an improved piping system by implementing hot water supply risers HWS and hot water return risers HWR extending vertically up the building with pressure reduction applied on a floor-by-floor basis as necessary to accommodate domestic plumbing fixtures 42. Each floor is supplied with a domestic hot water distribution main HWM for providing domestic hot water service throughout the floor to each suite 11. Even at the lower floors 33b, hot water recirculates at full hydrostatic pressures between the hot water heating system 31 or boiler, the supply risers HWS, and each distribution main HWM, so as to enable recirculation of return domestic hot water DHW through the hot water return riser HWR to the hot water heating system 31, the recirculation being performed without pumping. Therefore, on each lower floor 33b, a plurality of hot water pressure reducing valves 43 are provided, one at each suite 11 or for one or more of the plumbing fixtures 42. Each pressure reducing valve 43 reduces the pressure between the full pressure of the hot water main HWM and the actual domestic use fixtures 42 at domestic service pressures PD. At upper floors 33t, once the hydrostatic pressure in the hot and cold water supply risers HWS, CWS reduces to approximately 80-85 psig or less, pressure reducing valves 43 on both hot and cold water respectively are no longer required.
As shown in
Returning to
With reference also to
Circulation of hot water through the radiant walls 20 is effective by directing hot water DHW to each radiant wall 20 from the hot water distribution main HWM, and back to a collector main or hot water return main HWRM. Generally the hot water return main is arranged in a run parallel to the distribution main HWM and is in fluid communication with the hot water return riser. The hot water return main HWRM collects all the spent hot water collected from the radiant walls 20 for return to the hot water return riser HWR and the hot water heating system 31.
After having distributed hot water to all suites 11 on a floor 33, it is also preferable to install a flow control valve 47 between the hot water distribution main HWM and the return riser HWR. Preferably the flow control valve 47 is positioned between the hot water distribution main HWM, at about a last suite of the one or more suites in series, and the hot water return main HWRM. The valve 47 can be set at about ½ USgpm to assure that there is a continual flow and supply of domestic hot water in the distribution main HWM on each floor and adjacent each suite 11. This is important, especially in the summer months when no hot water is being used for circulation through the radiant walls 20, so as to provide hot water on demand to the fixtures 42. More preferably (not shown), in the case of very large residential suites, a flow control valve can be located (not shown) in each suite to assure that the hot water reaches the suite's faucets in less time.
As shown in
Circulation of cold water through the radiant walls 20 is effective by directing cold water to each radiant wall 20 from the cold water distribution main CWM, and back to a collector main or cold water return main CWRM. Generally the cold water return main CWRM is arranged in a run parallel to the distribution main CWM and is in fluid communication with the cold water return riser CWR. The cold water return main HWRM collects all the spent cold water collected from the radiant walls 20 for return to the cold water return riser HWR and the cooling system 41.
The thermostatic control for the suite 11 can be fit with a dump valve (not shown) to periodically permit flow therethrough to minimize stagnation in low demand situations or, for simplicity, can operate periodically even during usual demand situations.
In testing conducted in Calgary, Alberta, Canada, a system was tested which utilized domestic hot water DHW for both domestic use and heating of student residences using a radiant wall 20. Heating of adjacent rooms 10a,10b was simulated using a radiant wall 20 such as that arranged shown in
More specifically test measurements show that a single radiant wall 20, as tested, had a heating capacity of about 1500 W (4500 Btu/hr), which is sufficient to offset losses from typical residence rooms. It was recognized that end units and top floor units would require additional heating. The heat capacity was determined by calculating the heat transfer from the hot water supply and return temperature differential, the water flow rate, and the heat capacity of the water per unit volume. The industry guide for comfort assessment is ASHRAE's Standard 55-2004, Thermal Environmental Conditions for Human Occupancy. At Calgary, Alberta's 99% winter design temperature of −27° C. or 17° F., the proposed system, including window losses, maintained an interior room temperature of 11° C. (52° F.), which compared favorably to the minimum acceptable vertical surface temperature of 10° C. in terms of radiant asymmetry (ASHRAE 2004, p. 7).
The wall operating conditions were within conditions deemed acceptable by drywall and paint manufacturers. Prior art piping arrangements that have worn prematurely, having small hot water return water legs, are not used in this system. Further, it was found that it is easy to service radiant wall tubing relative to prior art piping systems such as in-slab radiant piping, because the tubing is enclosed within dry-walled areas.
The simulated system was tested with a hot water temperature of 150° F. (10° F. or 5.5° C. higher than the design temperature) and the maximum interior wall temperature temperatures observed was 118° F. (48° C.), which was 4° C. (7° F.) below the warranty limit. Drywall warranties typically allow temperatures up to 125° F. (or 51.5° C.) on a regular basis. Applicant understands that latex paints can be exposed to temperatures of up to 175° F. (80° C.) without degradation.
The whole building simulation model was used to estimate annual pump energy use with a conventional dual-piped domestic hot water and building heating system. Pump energy was estimated to be about 5% of total annual energy use. The annual cost saving was estimated to be about 33%, worth about $7,000 CAD at current energy prices. For a building with a local boiler plant, the 60° C. supply water temperature for the system allows a return water temperature suitable to permit condensing boilers to operate in condensing mode and attain efficiencies above 88%.
In the testing, the heated wall, at steady-state heat output, had a surface temperature of about 26° C., compared with a known normal range of 18-29° C. (65-85° F.). The supply-return temperature differential was a minimum of about 5.5° C. The flow rate of the water through the wall was 1 USgpm or 0.063 L/s. At a density of 1,000 g/L, this is a mass flow of 63 g/s. With the specific heat of water at 4.2 J/gC, the heat transferred was 245 J/s per ° C. or 245 W/° C. For a 6° C. temperature differential (the approximate difference at maximum heating), the heat transfer was then 1470 W (5000 Btu/hr). The heat loss was calculated for the double room, as its wall area is greater. The heat loss was estimated at about 1320 W at the design outdoor temperature with a temperature differential inside to outside of −49° C. The heat loss comprised 140W from a spandrel area of 2.4 m2, 709 W from 5.4 m2 of windows, 237W from 8.1 m2 of exterior wall, and lastly an estimated loss from infiltration of 233W.
The wall heat supply was therefore greater than the wall heat loss. The calculation neglected heat gains from occupants (about 70W per person) and any heat-generating equipment, which would provide an additional “cushion” against heat loss. A window thermal gradient calculation showed that the interior temperature at the −27° C. design temperature is 11° C.
While a preferred embodiment of the invention has been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention. Consequently, within the scope of the appended claims, it is to be understood that the invention can be practiced otherwise than as specifically described herein.
This application is a continuation-in-part of co-pending US application 10/851,349 entitled “MULTI-STORY WATER DISTRIBUTION SYSTEM” and which was filed May 21, 2004, the entirety of which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10851349 | May 2004 | US |
| Child | 11567660 | Dec 2006 | US |
