IMPROVED METHOD A~D APPAR~US FOR PRE~ L~ :
This invention relates generally to a method and appara~us for controlling the entry o~ ventilation air 5 into a building, and preheating th~ air with solar energy and recovered building loss~s.
BACKGROUND OF THI5_~VENTIO~
Commercial, industrial, domestic and apartment buildings r~quire ventilation, and it is common for the 10 natural leakage arvund door~, wall~ceiling join~s, stc.
found i~ standard building cons~ruction to allow sufficient air to ent~r the building. A pr~ssur~ drop from the exterior to the int~rior of th~ building can arise ~rom many factor~, such a~ high winds, exhaust 15 ~ans and combustion air ~or fuel~burning ~urnaces. This tends to draw outside air into th~ building through any crack or op~ning.
The problem with the con~entional approach is that the amount of ventilation air i~ not controll d, the 20 temperature in the building near th~ outsid~ walls is lower than averag~ and 1~5~ com~ortable, and additional heat must be provided to heat the outside ~lr to room te~perature during the heatinlg s~ason.
Thi~ pro~lem ha~ typically bo~n ~olved by ` - 25 installin~ gas, oil or ~l~ctric heater~ and air-moving ': fans to h~at thQ inco~ing ai~ Whe~ so~ar panels are llsf~d to heat a buildlng, air is recirculated from ~he bu:i lding through the collfafctor and back. During the heating sea~fofrl, the fambffifsnt tempf~rature is lower than 30 th~f room temperature, and thfsrefore a recirculating f fif~fflar collefff~itor operatff~ffffs at a much reduced efficiency level.
one of~ uqi hasffffff disfff~losed two methods and apparatufs ~.
~, which avoid using fconsumable ~3nfergy, like oil, to heat 3S incoming air for a building. Inste3d of simply recirculating intff rior air from the building through a '~ " -,'' 13~661q solar collector and back to the building, fresh make-up air for ventilation purposes is introduced into the building aPter first passing the air through a solar collector located on a south-facing wall of the building. In Canadian Patent No. 1,196,825, issued November 19, 1985, the colar collector consi~ts of glazing over a darkened wallO In U.S Patent NoO
4,774,932, issued October 4, 1988, th~ solar collector consi~ts of a darkenQd collector panel with corrugations running vertically, and collPcting means for withdrawing the heated air from vertical grooves ~ear the top of the pan21. -.
The latter method is less expenalYe for accomplishing the same goal. It~ efficiency in collecting the total heat created by th~ solar radiation in the collector panel can be reduced in some locations or on sloped wall The air rising in'the grooves heat~
up, becomes lighter and ~oves ~aster, and it~ initially laminar flow may turn into turbulent flow, mixing with cold air and 105ing heat to the ou*side. The taller the solar panel is, the more intensively the sun heats the panel, and the stronger a wind ~lows. The heat lo~s grows with the height of the panel as its te~perature is highest at the top. Thi~ 10~5 i~ aggravat~d if the panel does not have a s~lective coating.
~L DESCRIPTION OF ~HIS INV~NTION
~: We now have devised a new method and apparatus for :~-, acco~plishing the desired qoal at low cost and without I the above ef~iciency limitation~ for high panels.
More sp~cifically, this invention provides a ~ethod ~ : o~ preheatinq ventilation air for a building having a ¦ sun-facing outer sur~ace through which heat from the 3~ : interior of the building escapes, the method comprising ,~ the step~
3~ a~ providing on the sun-facing outer surface of the building a solar radiation-absorbent collector panel ? : ::
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having an inside surface and an outside surface, the collector panel defining an air collection space between its inside surface and said sun-facing outer surfac~, said outside surface being exposed to the ambience, the panel having, substantially uniformly distributed over the panel, a plurality of air inlet openings communicating with said air collection space;
b) heating outside air with solar heat from the collector panel and with heat being lost from the interiox of the building, and passing the heated air upwardly in laminar flow along te panel; and c) withdrawing heated outside air through the air inlet openin~s of the collectox panel and into the air collection space ~ehind the panel, using air-moving means having an inlet at the top of the air collection space and having an outlet within the interior o~ the building, the air-moving means establishing a negative pressure differential acroæs the collector panel with respect to the ambienoe.
Further this invention provides an apparatus for preheating ventilation air ~or a building having a sun-facing ouker surface through which heat from the interior o~ the building escapes, comprising:
a sunlight-absorben collector panel on the sun- :
facing ~urface, the panel having an inside sur~ace and an outside sur~ace, the colle~tor panel defining an air collection space between its inside surface and the outer surface of the building, said outside eur~aoe being exposQd to the ambience, the panel being provided with a 30 plurality o~ air inlet openings subskantially uni~ormly :-distributed over the panel and communicating with the said space between the panel and the wall, and :: air~moving means having at the top of the panel an inlet which communicates with the air collection space ~.
between the panel and said outer sur~ace ~or receiving : air that hao been heated during upward passage and drawn ':
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1 3 2 6 6 1 q in through the plurality of air inlet openings, and having an outlet within the interior of th~ building, the air-moving means establiihing a nRgative pressure diffsrential across the panel with respect to the S a~bience.
GENERAL DESCRI~TIO~ OF TH~ ~AWINGS
Several e~bodiments of this invention are illustrated in the accompanying drawing~, in which like nu~erals denote like parts throughout the several views, and in which:
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4 ~32661q Figure 1 is a perspecti~Ye view of a make-up or ven~ilation air system ~or a buildin~ constrlacted in acoordance with one embodiment o~ this invention;
Figure 2 i a vertic~l sectional view taken at the 5 1 ine A - A in Figure 1;
Figure 2a is a horizontal sectional vies~r taken at the line Il - ~ in Figure 2;
Figure 3 is a vertical s~ction through a second embodiment o~ thi~ $nventlon;
Figure 3a i~ a horizontal sectional view taken at the l ine B-B in Fi~re 3;
Figure 4 is a vertical sectlonal view through a third e~odiment OI this invention;
Figure 4a is an e~slarged view o~ a portion of 15 Fiqure 4;
Figure 5 i3 a v~r~ical s~c~isnal view taken through a ~ourl:h embodiment o~ thi~ inv~n1:ion;
Figur~ 5a i~ a horizontal sectional view taken at the lin~ B-B in Figur~ 5;
Figure 5b is a v~r~ic:al sectional ~riew, to a larger scale, o~ one portion o~ the embodimerlt shown in Figure : -5;
Flgure 5c i~ an elevation~l ~iew o f th~3 sam~
E~ortion a~ is ~hown in Figur~l 5b;
2S Figur~ 6 i~s a v@rtical ~ctional viaw through a furt~er embodl~n~nt o~ his inv~ntlon utilizing identical overlappixlg tile~ ~and h~ated air ~low to the air inlet op~ning~: -~i~r~; 6a i~3 a vertical ~ctiorlal view, to a larger - 30 3cale, o~ a portion of the e~bodim~an~ ~hown in Figur~ 6;
Figure 6b i~: an ~levational view of the portion shown in Fiç~ure 6a: and Figure~ 6c is an elevational view similar to Figure 6b, showing an alternative embodiment.
3S D~ P D~SCRI~O~ OF ~ DR~WI~IGS
l 3 2 6 6l q Attention is first direct~d to Figure 1 which shows a partly broken-aWay perspective view o~ a system Por : carrying out the present invention. A building wall is shown in part at 10 in the Figure, this being typically a block-and-brick composite structure~ As with all building walls~ even tho~e well-insulated, a steady heat loss is experienced through the wall when the outside temperature is below the inside temperature.
The wall 10 has an outer sur~ace 12 to which is 10 a~fixed a mounting plate 14. Secured to the mounting ~:
plate 14 are a number of corrugat~d sub~panels 16', 16", ~ , etc~ togeither con~tituting the collector panel 16 which is coated on the out~ide with a solar radiation absorbing material, ~uch as dark p~int.
F~r more desirable than dark paint would be a "selec~ive coating" with high absorption for solar radiation and little in~ra-red heat emission at temp~ratura~ occurring at the collector panel on a sunny -~
day, to keep to~al ener~y 10~3~e~ low.
In this embodi~ent o~ the invention, as previously mentioned, the p~nel 16 is co~po~ed Or a number of overlappi~g corrugated ~ub-p~n~l~ 16', 16", etc. From the top downwardly, they are ~pacQd from ~h~ mounting ~:~
: plate 14 at decreaaing distance~ leaving opening~ 6", 6~" etc. bs~wQen th~ sub-panel~, which serve as air inlet ope~ings through which the heated outside air ent~ir~ an alr collection spac2 15.
Th~ alr collestion space 15 iq de~ined between an~ -`
~ by the collec~or panels 16 and thQ ~ounting plate 14, 3 30 and in turn communicate~ with a plenum 22 at the top end - .
og the panel ~ h~ cro~ ection o~ the plenum 22 can ::
3~ be made to widen toward a ~an housing 30 by adjusting ~:
the po~ition of a separator wall 23 ~uch that .
substantially ~qual amount~ of air are gathered alon~ -~
35 t~ length o th~ plenum ~2 ~rom di~erent regions o~ ~ ~
: ~ th~ air collection ~pa~e 15. The fan hou ing 30 : -~ .
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6 13266t9 -contains a conventional fan or air impellf_r 31 and includes motorized dampers 32 which can bfe adjusted to allow air from the interior of the building to be mixed with heated air cominfg from the plffffffnum 22.
: 5 Co~fmunicating with thffsf housing 30 is a fabric air duct 34 which is preferably flamef retardant and made of polyfabric, the duct 34 being suspended by a plurality o~ duct hangers 36 ~frofm a suitably strung support wire or rod 38. The air duct has a plurf~lity of openings 40 ~:
through which the heated outside air cfan pass into the f building. By appropriately sizing the openings 40, the air ca~ enter the interior o~ the building as a high velocity air jet, thus promoting good mixing with the ~:~
air in the building and mini~izing ~trati~ication.
It is preferr~d that th~ duct 34 be lorated at the ceiling levfal ror the sake o~ conv~nience~in industrial :. and comm~rci~l buildinq~. Ot.h~r l~v~l~ and routlngs for the duct 34 may be chosen in apar~ment buildings.
1 Th~ fan within th~ hou8i.ng 30 would typically be siz~d to meet the ~entilatiorl requir~ment~ and eliminate any negative pressure in th~ building. A positive pressurè can be achieved with out3id~ air enterin~ the building through ths ~an 31, th~ air being h~ated by solar hea~, recoverefd building hf~at los~, and strati~ied heat ffound nfaar a high ceiling. Air can leavs ~he .:
building through cracks fand other openings where prf~vioufsly ~ir had enterfed.
: It ~ill 1 bQ noted that thff~ plenum 22 overhangs the corrugatf~fd panf~fl 16. When the ~un stands hiff3h in the 3 Of sky ~ thi~i arrangff~ment reduce~ overheating the air.
ernativ~ly, ~he p}~nu~ 22 can be provided with a by-pai~s damper 43 which c~n be opened when heated ~ir i~
nGt required- - .
It will ~urthQr be appr~ciated that the outside ;-.
air whlch isi heated e.g. by corrugated panel 16", will pas~ upwardIy as a well-de~ined laminar ~tream along the , . :
1 3~661 9 grooves 20" and will be drawn through the inlet openings 6" into the air collection space 15 well ~
be~ore either turbulence or wind can disturb the : -laminar hot-air stream to the point where heat could be 5 105t.
Assuming for the moment that there were no inlet -~
openings 61', 6"', and that the panel 16 were Yery high, then the laminar air streams would heat up further and would ris~ faster and faster until th~ well-defined ~ ~
10 laminar flow would turn turbulent, and would widen and ::~ .
heat up more outside air. Thi would mean that part of the heat would not be recovsre~O B
In constructions according to thi~ invention, turbulen~ ~low can be prevented, eYen in windy 15 condition~ the distanc~ betw~en inlet openings 6', 6" and 6"' i~ chosen to be suP~iciently ~hort. The more closely the inlet openings 6 are ~paced, e.g. the smaller the sub-panel height ~ in Figure 1, the small2r i~ the possibility of h~at b~ing last under adverse 20 conditions, such a~ ~he exi~tlence of a wind.
Figure 2 iæ a vertical ~l~ctional view o a variant o~ Figure 1 a~ the line A-A and Figure 2a ~how~ a horizontal æection~1 view o~ the ~tructure o~ Fi~ur~ 2 ::
at the line ~B. In FigurQ 2 there i~ a ~ourth tier of : ~
25 sub-panels identified by th~ num~ral 6"". Both Figures ~:
indicats that the opening~ 6', 6", etc. are placed at -:-th2 inner portion o~ each groove ~0', 20", etc. by : clo~ing o~f the r~mainder o~ the space between -~
overlapping panels, through the insertion o~ baffles 8 30 and by po~itionin~ the low~r plate o~ plenum 22 so as to .~
leave opening 6'. The ~ub-pan~l ~6"" is open at the ::
bottom as seen at 7 in Figur~ 2.
: ~ - Figur~ 3 is a v~rtical s~ctional view, similar to : : :Figure 2, of another embodiment of the invention. With . ~.
supports 19~ a corru~ated collector panel 16a is fastened to a w~ mounting plate 14a, at a uniform - ' ... :' 1 3~661 q distance from the bottom to the plenum 22. Equal sized inlet holes 6a are provided at the inner portion of the grooves 20 as is more clearly seen in Figure 3a. The latter is a horizontal sectional view of the structure ~: 5 of Figure 3 taken at line B-B. In order to ensur~ a uniform intake of heated air to the air collection space ~- 15 p~r unit panel area, the holes 6a near the panel top are spaced more widely apart than the holes 6a near the bottom of the panel 16. There are also holes 7a at the : 10 bottom.
It m~y be noted that equally spaced holes with decreasing diameters toward the panel top would be an alternative way to achieve the same goal of uniform air ~: intake across the collector panel ~6~
It should be noted further that the method s disclosed permit~ the con truction o~ collector panels . whose surfac~ temperature i~ the same across the panel.
It alternatively permit~ the construction o~ panels with increasing or decreasing temperature in any direction or any portion of t~e panel.
Figure 4 show~ a vertical sectional view of yet .i~, another embodiment o~ the im~ention. The corrugated panel 116 is spaced at some distançe from th~ wall or the wall mou~ting plate 114 n~ar the top of the panel, while being closer to the wa:Ll at the bottom. Identical .^i air inlet opening holes 106 are punched into the panel ~:
16 in the grooves 120 as see~ in ~hQ enlarged view of the panel 116 in Figure 4a.
Suitable support brackets l9a are used where 1! 30 fastening ls required. The inlet opening holes lO~ can be punched o~ site from the outside. The material of the - holes i5 not punched out, ~ut is rather di~placed as . shown in Figuræ 4a, in order to strengthen ~he rim 9 o~
the hole and thus maintain th~ original strength of the corrugated panel. If the holes, instead of being punched, are produced by a thermal melting method ':
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(similar to welding or supersonic heating), the hole material will ~orm a pre~erred heavy rim fxaming the hole.
Figures 1 to 4 present fa~ade constructions ~or ventilation air heating system~ which, as embodiments of this invention, are particularly suitable for industrial and commercial buildings. The invention, I however, is just as attractive for singl family dwellings and apartm~nt hous2s. Figures 5 and 6 show facade de$igns which appear particularly acceptable in home building.
Figure 5 shows a vertical section through a ~urther embodiment of the invention which consists of a v~rtical flat panel 16b made of ~xpanded metal sheet :1 i 15 with a dark outside house coloring, For archit ctural ::
reasons, the pan~l 16b is built up of small sub-panels, --each attached to and supported by vertical support-walls .
17b as shown in the horizontal s~ctional view of Figure 5a, taken at the line B-B in Figure 5~
Figures 5b and 5c are an enlargement of the panel 16b of Figure 5, and an elevat:ional view o~ the panel, respectively. The air inlet openings 6b consist of the slits cut into the metal sheet: 16b by the conventional I metal expanding-punch pre~. The flat m~tal sheet is ¦ 25 broken up into a sucses ion o~ nearly overlapping miniatur~ ~ub~panels 16b', eas:h row interstitial to the -.. -I next, creating an attractive ~Lmage ~or a house ~acade. :~
I The air collection space 15b behind the panel 16b ~ has a ~ros~-~ection which decreases from the plenum 22 ~:~
i 30 to~ard the bot~om, by virtue o~ ~hPrmal insulation ¦ layers 24b increasing in thickness, The insulation layers are enclo~ed in a thin m~tal film 25b. -j Figure 6 i3 a ~ectional view o~ another em~odiment : :~
o~ the invention, showing a "porous" solar collector ~: 35 panel acceptable as a facade for dome~tio housing. The panel 216 is made up of a plurality of overlapping small ':
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sub-panels 216', 216", etc~ shown enlarged in Figure 6a.
The two Figures indicate that the construction o the - panel is applicable as a roof covering as well as a south-wall ~acade. Ra~ters 217 and boards 211 serve to support the sub-panels 216', 216'l, etc. The thickness of the individual panel determines the height of th~ air inlet openings 206. The overlap on the sides of the sub-panels limits the width of the openings. Figure 6b is an elevational view of the panel 216, and indicates the heated air flow to the air inlet openings 206. From the openings 206, the air flows to the plenum 222 x through the air collection channel 215, in part defined by ducting material 275 covering the thermal insulation 224 of the attic room and the rafters 217.
The sub-panels may be made of a large variety of ,, ma~erials such as ceramic tiles, roofing or siding shingles, metal tiles with a selective coating of '~ desired coloring, glass pla$e with photovoltaic evaporated film~ or other types o~ photovoltaic 20 electric panels etc. ~:
The use of photovoltaiz panels as collector panels . 16 in accordance with this invention is o~ particular interest for the futura. Phc~tovoltaic cells operate well under a tempsrature of 30C and with decreasing : .
ef~iciency ~t high~r tamperatures~ They need to be cooled ~or be~t p~rfo~mance in summer. Using water as a cooling agent lead~ to expensive constructions. Using ventilation air ~or photoYoltaic cell cooling in accordance with this embodiment of ~he invention ~atisfies both requirements without additional cost.
Fiqures 6 - 6b ~how:that the inlet airflow provides a very efficient heat transfer from the panel~ 216 to the ~: air. The panels are secured by fastening means 241 which may be used in addition as electrical contacts.
Figu~e 6c shows an alternative t le construction to ~:~ that illustrated in Figure 6b. In Figure 6c, the .
1 3266 1 q individual tile5 are hexagonal and are identi~ied by the numerals 316', 316'1, 2tC. The air-intake openings are identified with by the nuffleral 306.
While several embodiments of this invention have been illustrated in the accompanying drawings and described hereinabove, those skilled in the art will . appreciate that changes and modifications may be made ::
,' therein without departing from the essence of this invention, as set forth in the appended claims.
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