Note: Descriptions are shown in the official language in which they were submitted.
CA 02570122 2006-12-06
1 TEMPERATURE CONDITIONING RADIANT WALL SYSTEM FOR BUILDINGS
2
3 FIELD OF THE INVENTION
4 The present invention relates to systems for the heating and cooling
of buildings, reduction in capital expense, and the distribution of water for
6 minimizing the number of piping risers and avoiding over-pressure supplies
7 through the strategic placement of pressure reducing valves.
8
9 BACKGROUND OF THE INVENTION
Heating and cooling systems for multi-story buildings typically use
11 specifically supplied and circulated hot and cold water for delivery to
heat
12 exchangers. Traditionally, room-by-room heating, and air conditioning
systems in
13 large buildings have been, what are known in the art, as four-pipe fan-coil
14 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
16 provide for zonal temperature control. Heating or cooling is provided by
having
17 the fan circulate air over a coil that is accessing either the hot or the
chilled-water
18 piping system, respectively. Water distribution systems for multi-story
buildings
19 also typically comprise various arrangements of water supply and returns.
Conventional 8 floor zones extend risers up through all suites with
21 the associated water noise for the lower suites and the large number of
risers.
22 Each riser is associated with fire blocking and challenges at bulkheads and
23 cross-over floors.
1
CA 02570122 2006-12-06
1 To date, choices for heating and cooling commercial or multi-suite
2 buildings have been limited and equipment such as fan coils are an
expensive,
3 but known, solution.
4 Multi-story buildings further introduce challenges including problems
related to hydrostatic pressure variation from floor to floor. In a 24 storey
building
6 the pressure at the lowest floor may be about 130 psig so as to maintain 40
psig
7 at the highest of the upper floors or roof where the hydraulic head is at
its
8 minimum. To supply a 72 storey building from a single water supply riser
would
9 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
11 pressure in a domestic hot water system will ensure return flow to the hot
water
12 boilers but such pressures are too high for domestic purposes.
13 There is a need for a reduction in redundant piping, elimination of
14 noise in suites, lower capital cost and more efficient systems in the
heating,
cooling and distribution of domestic water in high rise buildings. Applicant
16 addresses these shortcomings and incorporates further improvements to
heating
17 and cooling systems, some of which can be incorporated with domestic water
18 distribution.
2
CA 02570122 2006-12-06
1 SUMMARY OF THE INVENTION
2 Applicant has provided a system which significantly reduces the
3 piping needed to supply domestic hot and cold water to one or more units,
4 residences or suites in high rise buildings, solves issues associated with
the
supply of water at pressures above desired domestic use pressures, and
6 incorporates novel heating concepts for multi-residence buildings. The
number of
7 risers throughout can be reduced in number by more than an order of
magnitude.
8 Noise issues associated with flow in risers extending through each suite is
9 eliminated.
Applicant has recognizes that use of domestic water system for
11 heating and cooling using partitioning walls as radiant walls, enables
heating and
12 cooling of adjacent rooms and better utilizes existing domestic water
systems for
13 minimizing capital expenditures such as through the reduction or
elimination of
14 fan-coil or hydronic radiant panel devices.
The partitioning walls condition room temperatures by acting as a
16 cold or hot radiant wall either using hot domestic water for heating, or
using
17 chilled domestic water for cooling, or alternating therebetween using
thermostatic
18 valves for circulating either the heated domestic water or chilled domestic
water.
19 Applicant further recognized that several aspects of pressure
control at lower floors provides significant advantages. Use of full pressure,
21 variable over elevation, domestic cold and hot water systems and pressure
22 reducing valves as required for domestic service only, eliminates floor to
floor
23 risers and remarkably reduces the numbers of piping runs. Pressure and flow
24 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
3
CA 02570122 2006-12-06
1 common risers at full pump pressure at full hydrostatic head. Further, the
system
2 has several solutions for ensuring hot water availability and avoiding
stagnation
3 which can occur in some domestic lines, contrary to public safety and
contrary to
4 plumbing regulations in some jurisdictions.
In one embodiment, the system has a domestic hot water supply
6 riser and a hot water return riser. At each serviced floor, a domestic hot
water
7 distribution main extends from the hot water supply riser to each of one or
more
8 suites and returns to the hot water return riser. On each floor, typically
lower
9 floors, at which a riser pressure is higher than preferred service pressure
for
domestic plumbing fixtures, a pressure reducing valve is situated at least
11 between the distribution main and domestic use fixtures in the suites for
reducing
12 the pressure of the cold and the hot water as required. Coupling of the
heating
13 systems directly off of the supply riser at full water pressure and to the
hot water
14 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
16 heating system without a need for further pumping. Further, implementation
of a
17 substantially constant circulation of hot water through the hot water
distribution
18 main ensures hot water is available on demand. Additionally, when heating
is
19 not required, regular and periodic circulation through the hot water
distribution
main avoids stagnation of the domestic hot water supply.
21 As a result, applicant has determined that up to 70% can be saved
22 on the fluid piping in a building and 20% on the cost of the entire
mechanical
23 system. Supply risers no longer run through suites, eliminating noise.
Bulkheads
24 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
4
CA 02570122 2006-12-06
1 water to heating and cooling systems. With reduced numbers of risers comes
2 less wasted floor area for accommodating piping. Use of domestic hot water
for
3 heating, and as desired domestic cold water for cooling reduced capital cost
by
4 reducing or eliminating fan coils and other equipment.
In one broad aspect, a system for temperature conditioning multiple
6 serviced floors of a high rise building is provided, each floor having one
or more
7 suites having interior and exterior walls and having plumbing fixtures being
8 serviced with at least domestic hot water. Such a system comprises:
providing at
9 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
11 domestic hot water to one or more suites on the floor. The domestic hot
water is
12 thermostatically controlled through radiant tubing installed in one or more
radiant
13 walls in a suite, of one or more suites, for heating the suite. For each
floor at
14 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
16 the hot water to the domestic use fixtures is reduced to about the first
threshold
17 pressure using one or more pressure reducing valves situated between the
18 distribution main and the domestic use fixtures of each suite.
19 Preferably, the system further comprises a domestic cold water
distribution main for each serviced floor at a supply pressure. In embodiments
21 where cooling is not required, such as in moderate climates, and for each
floor at
22 which the supply pressure of the domestic cold water supply at each floor
is
23 above a second pressure threshold, typically the suitable domestic service
24 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
5
CA 02570122 2006-12-06
1 for the radiant walls, one can maintain the domestic cold water distribution
main
2 at full pressure for radiant wall circulation and, as applied to the
domestic hot
3 water, reduce the water pressure of the cold water to the domestic use
fixtures to
4 the second threshold pressure using one or more pressure reducing valves
situate between the full pressure cold water distribution main and the
domestic
6 use fixtures of each suite.
7 Preferably, a heating system or heater provides heated hot water to
8 each domestic hot water distribution main, and a hot water return riser
returns hot
9 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
11 distribution main, and a cold water return riser retums cold water from
each
12 distribution main to the chiller.
13 For heating and cooling using radiant walls, a pair of three-way
14 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
16 three-way valve controls whether the thermally spent water returning from
the
17 radiant wall is returned to the cold water return riser or the hot water
return riser
18 respectively.
19 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
21 substantially constant flow of hot water for ensuring a substantially on-
demand
22 hot water response at the domestic use fixtures. Preferably the flow
control valve
23 is positioned between the distribution main after the last serviced suite,
and a
24 return main to the return riser. The radiant walls and other heating loops
can be
6
CA 02570122 2006-12-06
1 provided with thermostatically controlled valves having periodic dump
features to
2 avoid stagnation.
3 Typically radiant wall are provided on interior walls of a suite for bi-
4 directional heating. More preferably, suites adjacent an exterior wall, and
similarly adjacent utility or common areas such as stairwells, can be provided
6 with additional radiant tubing installed in the floor such as adjacent the
exterior
7 wall. As necessary, walls between adjacent suites can be fit with radiant
walls,
8 but are arranged for uni-directional heating to the suite having the
thermostatic
9 control.
7
CA 02570122 2006-12-06
1 BRIEF DESCRIPTION OF THE DRAWINGS
2 Figure 1 is a schematic plan view of an arrangement of a hot wall
3 heating system arranged in an intervening partition wall dividing two rooms
of a
4 suite;
Figure 2 is a schematic elevation view of radiant tubing arranged in
6 a radiant wall and operating at full hot water supply pressures;
7 Figure 3A is a schematic elevation of a high rise building
8 implementing some of the heating and cooling features of the present
invention;
9 Figure 3B is a schematic elevation of a high rise building
implementing only heating features of the present invention;
11 Figure 3C is a schematic of adjacent suites of a lower floor
12 according to Fig. 3A and illustrating the hot and cold water distribution
mains and
13 pressure reducing valves to fixtures;
14 Figure 4 is a schematic plan view of an arrangement of a hot wall
heating system arranged on the facing wall of a single suite to avoid heat
transfer
16 or loss through the facing wall, such as to an adjacent suite or non-suite;
17 Figure 5 is a schematic plan view of an arrangement of a hot wall
18 heating system arranged in an intervening partition wall dividing two
suites where
19 one of the two suites is adjacent an exterior wall and the radiant tubing
is
expanded to include auxiliary floor heating; and
21 Figures 6A and 6B illustrate the domestic hot water and domestic
22 cold water piping to typical plumbing fixtures in a suite.
8
CA 02570122 2006-12-06
1 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
2 Generally, as shown in Fig. 1, adjacent rooms 10a,10b within a
3 suite 11 are separated by a walls 12, such as an interior partitioning wall
13.
4 During seasons where the rooms 10a,10b require heating, one or more of the
walls 12 can be operated as hot radiant walls 20. In the case of an interior
6 partitioning wall 13 operated as a radiant wall 20, heat radiates bi-
directionally
7 into the suite 11 in both directions to adjacent rooms 10a,10b. An interior
8 partitioning wall 13 within a suite 11 is a convenient embodiment for a bi-
9 directional radiant wall 20 wherein a suite occupant can control the radiant
output
solely for their suite 11. One is less inclined to operate a party wall 14,
located
11 between adjacent suites 11a,11b, as a bi-directional radiant wall 20
because
12 thermostatic control by an occupant in one suite 11a can also affect the
comfort
13 of an occupant of the adjacent suite 11 b. Options include either avoiding
the
14 implementation of radiant walls 20 in a party wall between suites 11 a,11 b
or
instead to configure such radiant walls 20 for uni-directional radiant thermal
16 control.
17 While referred to as a "radiant" wall, which suggests radiant heat
18 transfer, other aspects of the principles of heat transfer are also
inherent and
19 contemplated, such as conduction to the wall surface and convection
therefrom.
Further, radiant walls 20 can provide thermal control including either heating
and
21 cooling. While examples are provided in terms of a hot radiant wall 20,
heated
22 using domestic hot water DHW, temperature conditioning or thermal control
using
23 a radiant wall 20 can equally include cooling using a circulation of
domestic cold
24 water DCW. Temperature adjusted water, which is circulated through radiant
9
CA 02570122 2006-12-06
1 walls 20 for temperature control, is generally termed herein as thermal
water and
2 more specifically as domestic cold water DCW or domestic hot water DHW.
3 With reference also to Fig. 2, the radiant wall 20 comprises thermal
4 tubing 21, such as cross-linked polyethylene tubing (PEX), for example
AQUAPEX available from Wirsbo Company of 4925 W 148th Street, Apple
6 Valley MN, 55124, USA, located within the cavity of the partition wall 13.
The
7 tubing 21 is arranged in a serpentine manner to distribute the tubing in the
wall.
8 The tubing 21 can be overlapped as necessary and without concem. Tubing 21
9 can be arranged in up-and-down orientation (not shown) or a side-to-side
orientation (shown) which can have advantages if the system needs to be
11 drained at come point. Thermal water is circulated through the tubing 21 as
12 necessary to meet the thermal loads, typically heating and can alternately
include
13 cooling. Heating loads for each suite 11 a,11 b ... are provided from the
domestic
14 hot water DHW provided at each floor. Where necessary, cooling loads are
provided from the domestic cold water DCW, preferably chilled, provided at
each
16 floor. The length of thermal tubing 21 fit to the radiant wall 20 provides
sufficient
17 surface area to meet the design thermal loads as is known to those of skill
in the
18 art.
19 Within a radiant wall 20, the thermal tubing 21 is positioned
sufficiently offset within the wall 20 from either wall surface to avoid
accidental
21 punctures from screws and other fasteners.
22 An implementation of various embodiments in the context of a high
23 rise building 30 is set forth in Figs. 3A - 3C and discussed later below.
24 With respect to the radiant walls 20, and in Fig. 4, where heating is
desired only to one side of the radiant wall 20, such as at a party wall 14,
the wall
CA 02570122 2006-12-06
1 20 is configured for directing the heat H into the room 10 only which is to
be
2 heated. Again, the thermal tubing 21 is also positioned sufficiently offset
within
3 the wall 11 from the wall surface to avoid accidental punctures from screws
and
4 the like, however, heat transmission is emphasized from one side of the wall
20,
either through heat reflective surfaces, offsetting the radiant tubing 21 more
6 towards the wall surface adjacent the room to be heated, or through
selective
7 insulation 15 or a combination thereof.
8 In Fig. 5, end suites are subject to greater heat loss through
9 windows and an additional exterior wall and can be fit with additional
thermal
tubing 21, such as in an auxiliary radiant heating loop 22. The loops 22 are
11 embedded in the floor and provide heat H adjacent the areas most
susceptible to
12 the additional heat loss or gain due to exterior influences. The loop 22
can be in
13 plumbed to circulate in series with radiant wall 20, such as after the
thermal
14 tubing 21 has passed through the radiant wall and resulting in lesser
thermal
gradient. Depending on the plumbing arrangement, alternatively the loop 22 can
16 be plumbed in parallel with the radiant wall for maximal output of heat H.
17 Domestic hot water DHW and domestic cold water DCW are also
18 typically provided at each floor of a multi-story building and are
circulated to each
19 suite 11.
Fig. 3A is a schematic illustration of a typical arrangement of piping
21 for radiant walls 20 for a high rise, multi-story building 30. At least a
heating
22 system 31 such as a boiler or heat pump is provided for the heating and
23 circulation of heated domestic hot water DHW through a hot water supply
riser
24 HWS to each floor 33. Domestic hot water returns to the heating system 31
through a hot water return riser HWR. The heating system can be located at a
11
CA 02570122 2006-12-06
1 convenient location. Hot water heaters and boilers with heat exchangers for
2 heating domestic hot water are often at roof level. Heat pumps, which can
heat
3 or cool domestic water are typically located in the basement levels adjacent
4 ground loops.
The hot water supply riser HWS and hot water return riser HWR
6 extend to each of the multiple services floors 33 and are fluidly connected
to the
7 hot water heating system 31. Water pressure of the domestic hot water DHW in
8 the risers HWS,HWR varies with elevation due to the variation in hydrostatic
9 head.
The heating system 31 is illustrated at the top floor but could be
11 located at any elevation in fluid communication with the supply and return
risers
12 HWS,HWR.
13 Further, on very tall buildings, vertical zones of multiple floors can
14 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
16 for each zone a booster pump which supplies water to the zonal hot and cold
17 water risers to ensure a pressure exists therein which, at a highest floor
of the
18 zone is at least domestic service pressure, and at the lowest floor of the
zone, is
19 at or below a maximum booster system pressure.
Where cooling functions are desired, a cooling system 41 such as a
21 heat pump or chiller is also provided for circulation of chilled domestic
cold water
22 DCW through a chilled water supply riser CWS to each floor 33. Domestic
cold
23 water returns to the cooling system 41 through a chiller water return riser
CWR.
24 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
12
CA 02570122 2006-12-06
1 domestic cold water in the risers CWS,CWR varies with elevation. The
2 temperature of the chilled water is pre-determined to avoid condensation
issues
3 as is known to those skilled in the art.
4 With reference to Figs. 3A and 3C, each serviced floor 33
comprises a plurality of suites 11a,11b ... serviced with domestic cold water
6 DCW and domestic hot water DHW, supplied by the hot water distribution main
7 HWM and cold water distribution main CWM respectively. For illustrative
8 purposes only, one suite 11a is shown plumbed to the mains HWM,CWM.
9 Further, for illustrative purposes only, a pedestal sink 44 is provided in
suite 11 a
as an example of a domestic use fixture 42.
11 Characteristic of multi-story buildings 30, each successive higher
12 floor 33 experiences a corresponding loss of hydrostatic head and water
13 pressure. In order to provide water under sufficient domestic service
pressure PD
14 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
16 threshold PH, which is often greater than the desired domestic use pressure
PD,
17 so that a minimum domestic pressure PL can be maintained at a highest of
the
18 upper floors 33t. The pressure threshold PH at the lowest of the lower
floors 33b,
19 is typically at a pump pressure for delivering at least the minimum
domestic
pressure PL to the upper floors 33t.
21 Similarly, the cold water supply riser CWS also extends either up or
22 down the building 30, and is subject to the same variation in hydrostatic
head and
23 will operate at substantially the same variable pressures. Accordingly, the
lowest
24 floors 33b are supplied at the greatest pressure with water pressure
diminishing
13
CA 02570122 2006-12-06
1 at higher elevations to the upper floors 33t which are supplied at the
lowest
2 pressure PL.
3 Domestic facilities or fixtures 42, such as toilets, sinks and laundry
4 hook-ups have a maximum service pressure and preferably operate at domestic
service pressures PD. The fixtures plumbed with domestic water will a
preferred
6 hot water threshold pressure and a cold water threshold pressure. Usually
the
7 threshold pressures for the DCW and DHC at the fixtures 42 is the same
8 domestic service pressure PD. As shown in Figs. 6A and 6B typical plumbing
9 fixtures in a suite include a water closet or toilet WC (DWC only), laundry
L (DHW
and DCW), shower SH (DHW and DCW) and a sink SK (DHW and DCW).
11 The pressure of the domestic hot water DHW and domestic cold
12 water DCW in the risers HWS,CWS at lower floors 33b can be higher that
13 acceptable domestic service pressures PD. Accordingly, the cold water DCW
and
14 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
16 each suite 11 for reducing the pressure of the hot water DHW directed to
17 plumbing fixtures 42. The valve 43 is located between the hot water
distribution
18 main HWM, which circulates heating water at full riser pressure through
radiant
19 walls 20, and the fixtures 42, which are fed at reduced domestic service
pressures Po.
21 Upper floors 33t do not require pressure reduction as the water
22 pressure is already between the minimum pressure PL and a preferred
domestic
23 service pressure Po. Accordingly, the domestic plumbing fixtures 42 for
upper
24 floors 33t are directly plumbed to the distribution main HWM at the full
pressure
of the hot water supply riser HWS.
14
CA 02570122 2006-12-06
1 Further, in Fig. 6B, before the water returns from a serviced floor
2 33, a thermal tubing 21 from the hot water distribution main HWM can also be
3 directed to ancillary, non-suite areas such as stairwells 50. In this
arrangement
4 shown in Figs. 6A and 6B, and according to Fig. 3B in which cooling is not
required, the domestic cold water DCW is not circulated. Therefore, a pressure
6 reducing valve 43 need only be provided (not shown) between the cold water
7 supply riser CWS and the cold water distribution main CWM as domestic cold
8 water is only used for domestic use fixtures 42. Accordingly, pressure
reducing
9 valves are not needed, nor illustrated, between the cold water distribution
main
CWM and a return riser, as there is no need for a cold water return main or
riser.
11 As discussed in Applicant's co-pending application 10/851,349, filed
12 May 21, 2004 to Applicant and published as US-2005-0183773-A1 on August 25,
13 2005, and discussed in the context of the use of fan coils as the preferred
heating
14 and cooling equipment, improved efficiencies and comfort are achieved using
an
improved piping system by implementing hot water supply risers HWS and hot
16 water return risers HWR extending vertically up the building with pressure
17 reduction applied on a floor-by-floor basis as necessary to accommodate
18 domestic plumbing fixtures 42. Each floor is supplied with a domestic hot
water
19 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
21 hydrostatic pressures between the hot water heating system 31 or boiler,
the
22 supply risers HWS, and each distribution main HWM, so as to enable
23 recirculation of return domestic hot water DHW through the hot water return
riser
24 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
CA 02570122 2006-12-06
1 pressure reducing valves 43 are provided, one at each suite 11 or for one or
2 more of the plumbing fixtures 42. Each pressure reducing valve 43 reduces
the
3 pressure between the full pressure of the hot water main HWM and the actual
4 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
6 reduces to approximately 80 - 85 psig or less, pressure reducing valves 43
on
7 both hot and cold water respectively are no longer required.
8 As shown in Fig. 3B, in instances where cooling is not required, the
9 cooling system 41 for the domestic cold water DCW is generally not required
at
all, and the domestic cold water DCW can be pressure reduced with valves 43 at
11 each lower floor 33b and a cold water distribution main CWM for each lower
floor
12 33b can operate at domestic service pressures Pp.
13 Retuming to Fig. 3A, where cooling through radiant walls 20 is also
14 an option, the cold water supply riser CWS supplies cold water to a cold
water
distribution main CWM for circulation of cold water to each suite on the floor
33.
16 Again, for lower floors 33b, pressure reducing valves 43 are provided
between
17 the cold water distribution main CWM and the domestic use fixtures 42.
18 With reference also to Fig. 3C, domestic hot water and domestic
19 cold water is provided to radiant walls 20 in two adjacent suites 11 a,11 b
through
the hot water distribution main HWM and cold water distribution main CWM
21 respectively. The two suites 11 shown are located adjacent an end of a run
of
22 the distribution mains HWM,CWM. In order to implement altemative heating or
23 cooling through the radiant walls 20, a first three way valve 45 is
provided for
24 alternately connecting an inlet end of the thermal tubing to the hot water
distribution main HWM for heating the radiant wall 20 and the cold water
16
CA 02570122 2006-12-06
1 distribution main CWM for cooling the radiant wall. Under thermostatic
control,
2 either hot water DHW flows through the thermal tubing 21, or chilled water
flows
3 through the thermal tubing 21. The thermally spent water flows out a
discharge
4 end of the thermal tubing 21 for return to one of the risers HWR,CWR.
Preferably
a second three way valve 46 alternately connects the discharge end of the
6 thermal tubing to the hot water return main HWRM while heating, and the cold
7 water return main CWRM while cooling. Both the first and second three-way
8 valves 45,46 can be controlled by a conventional thermostatic controller
(not
9 shown).
Circulation of hot water through the radiant walls 20 is effective by
11 directing hot water DHW to each radiant wall 20 from the hot water
distribution
12 main HWM, and back to a collector main or hot water return main HWRM.
13 Generally the hot water return main is arranged in a run parallel to the
distribution
14 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
16 radiant walls 20 for return to the hot water return riser HWR and the hot
water
17 heating system 31.
18 After having distributed hot water to all suites 11 on a floor 33, it is
19 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
21 positioned between the hot water distribution main HWM, at about a last
suite of
22 the one or more suites in series, and the hot water return main HWRM. The
23 valve 47 can be set at about '/2 USgpm to assure that there is a continual
flow
24 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
17
CA 02570122 2006-12-06
1 no hot water is being used for circulation through the radiant walls 20, so
as to
2 provide hot water on demand to the fixtures 42. More preferably (not shown),
in
3 the case of very large residential suites, a flow control valve can be
located (not
4 shown) in each suite to assure that the hot water reaches the suite's
faucets in
less time.
6 As shown in Fig. 3C, radiant walls 20 are both heated and cooled.
7 Pressure reducing valves 43 are positioned, in each suite 11 a,11 b, between
the
8 mains HWM,CWM and the fixtures 42 for the particular suite 11. Accordingly,
9 pressures need not be reduced for use with the radiant wall 20.
Circulation of cold water through the radiant walls 20 is effective by
11 directing cold water to each radiant wall 20 from the cold water
distribution main
12 CWM, and back to a collector main or cold water return main CWRM. Generally
13 the cold water return main CWRM is arranged in a run parallel to the
distribution
14 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
16 the radiant walls 20 for return to the cold water return riser HWR and the
cooling
17 system 41.
18 The thermostatic control for the suite 11 can be fit with a dump
19 valve (not shown) to periodically permit flow therethrough to minimize
stagnation
in low demand situations or, for simplicity, can operate periodically even
during
21 usual demand situations.
22 In testing conducted in Calgary, Alberta, Canada, a system was
23 tested which utilized domestic hot water DHW for both domestic use and
heating
24 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
18
CA 02570122 2006-12-06
1 Fig. 1. The radiant wall 20 was formed by threading plastic pipe as the
thermal
2 tubing 21 through the metal studs in the partition wall 13, with local
thermostatic
3 control of the flow of hot water DHW to each occupant's room. The testing
4 investigated the adequacy of thermal performance (including comfort and
thermal
output), durability of building systems (include pipe, drywall, and paint
lifetime),
6 and the significance of energy savings. The assessment determined that the
7 system met the above criteria.
8 More specifically test measurements show that a single radiant wall
9 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
11 end units and top floor units would require additional heating. The heat
capacity
12 was determined by calculating the heat transfer from the hot water supply
and
13 return temperature differential, the water flow rate, and the heat capacity
of the
14 water per unit volume. The industry guide for comfort assessment is
ASHRAE's
Standard 55-2004, Thermal Environmental Conditions for Human Occupancy. At
16 Calgary, Alberta's 99% winter design temperature of -27 C or 17 F, the
proposed
17 system, including window losses, maintained an interior room temperature of
18 11 C (52 F), which compared favorably to the minimum acceptable vertical
19 surface temperature of 10 C in terms of radiant asymmetry (ASHRAE 2004, p.
7).
The wall operating conditions were within conditions deemed
21 acceptable by drywall and paint manufacturers. Prior art piping
arrangements
22 that have worn prematurely, having small hot water return water legs, are
not
23 used in this system. Further, it was found that it is easy to service
radiant wall
24 tubing relative to prior art piping systems such as in-slab radiant piping,
because
the tubing is enclosed within dry-walled areas.
19
CA 02570122 2006-12-06
1 The simulated system was tested with a hot water temperature of
2 150 F (10 F or 5.5 C higher than the design temperature) and the maximum
3 interior wall temperature temperatures observed was 118 F (48 C), which was
4 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
6 that latex paints can be exposed to temperatures of up to 175 F (80 C)
without
7 degradation.
8 The whole building simulation model was used to estimate annual
9 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
11 energy use. The annual cost saving was estimated to be about 33%, worth
about
12 $7,000 CAD at current energy prices. For a building with a local boiler
plant, the
13 60 C supply water temperature for the system allows a return water
temperature
14 suitable to permit condensing boilers to operate in condensing mode and
attain
efficiencies above 88%.
16 In the testing, the heated wall, at steady-state heat output, had a
17 surface temperature of about 26 C, compared with a known normal range of 18-
18 29 C (65-85 F). The supply-retum temperature differential was a minimum of
19 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
21 of water at 4.2 J/gC, the heat transferred was 245 J/s per C or 245 W/ C.
For a
22 6 C temperature differential (the approximate difference at maximum
heating),
23 the heat transfer was then 1470 W (5000 Btu/hr). The heat loss was
calculated
24 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
CA 02570122 2006-12-06
1 inside to outside of -49 C. The heat loss comprised 140W from a spandrel
area
2 of 2.4 m2, 709 W from 5.4 m2 of windows, 237W from 8.1 m2 of exterior wall,
and
3 lastly an estimated loss from infiltration of 233W.
4 The wall heat supply was therefore greater than the wall heat loss.
The calculation neglected heat gains from occupants (about 70W per person)
6 and any heat-generating equipment, which would provide an additional
"cushion"
7 against heat loss. A window thermal gradient calculation showed that the
interior
8 temperature at the -27 C design temperature is 11 C.
9 While a preferred embodiment of the invention has been illustrated
and described, it will be appreciated that various changes can be made therein
11 without departing from the spirit and scope of the invention. Consequently,
within
12 the scope of the appended claims, it is to be understood that the invention
can be
13 practiced otherwise than as specifically described herein.
21
