Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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SPECIFI~ATION
Field of the invention
The rullo/.~;ng disclos~re relates to air condi~ioner:~ known as heat pumps, in particular to the
category known as reverse air cycle heat pumps~ that can be used for comfort air conditioning in homes,
offices, restauranb etc.
Description of the prior art
The pr~oi"i"dn~ heat pump in use today utilizes the reversible r~ligerant cycle. In this kind
of machinery a conder,sir-g unit, comprised of con,pr~ssor, condenser (the latter has to function as an
po,~Lur in the heating mode), ouWoor fan motor and various control circuitry, is located in an ~ osed
position outside the building. The indoor unit, consisling of the evaporak~r (the latter has to function as a
condenser in the heating mode) and the ~ ,uansion device, is located in either an existing furnace
cabinet or in a dedicated enclosure with a blower fan and connected to a duct system. The indoor and
ouWoor units are interc,onne~ d by lefli~erdL,on tubing and control wiring. A change-over valve is utilized to
direct liquid refrigerant into either the indoor evaporator or the outdoor evaporator depending on whether
cooling or heating is being called for.
This type of system has several disadvdr,lages the principal one being as follows: A heat
pump is I ~e~d to carry out the two tasks of either heating or cooling of air. Particularly in northern
cli."dlas the demand for heating PY~;eeds the demand for cooling by a significant factor. A heat pump unit
therefore has to be seized large enough to satisfy the heating demand, resulbng in an apparatus that is far
too powerful in the cooling mode, and although capable of lov,ering the air temperature very rapidly, only
r~ ly small quantities of moisture are U~ld~tl~d because de-humidifying is only carried out during
operation of the unit. It is for this reason that a slightly under~ ed apparatus operating continuously
would represent the ideal choice for cooling and de-humidifying. Obviously this ~rp~-~hls would only have
relatively small heating capacity in the heating mode.
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My proposed heat pump design will solve this problem in two steps:
- Firstly the unit, - sized sufficiently large to handle the heat load during the heating season -, will cool down the
air to the desired temperature in the cooling mode.
- Secondly the unit will switch to the de-humidifying mode and continue to remove moisture until the
desired humidity level is reached.
It can thus be seen, that with this multiple-function c~p~hilily the unit can be sized for heating
demand, whilst still retain the full capabiliLy to cool and de-humidify to required levels. It is this dual
function that overcomes the main draw-back of the reversing refrigerant heat pump.
The second advantage is that each coo,pressor-col~denser-eYapGrcltor design can be na,(il"i,ed for
operating efficiency because the condenser and evaporator are dedicc,led to their respective functions of
condensing and evaporaling of the rt,r,igerdn~, whilst in todays design the evapo,dtor and condenser have to
int~,rchange tasks with the resulting compromises regarding the dimensions and design of these items.
A third advantage is that the entire unit can be asse",bled in a single cabinet and typically in~t"~d in a
basement. Thus the apparatus is not exposed to inclement climatic cond;Lions which also facilit~tes
servicing. A coi"p!~e inst~ tion requires only two air ducts communicating with the outdoors, one serving
as the inlet and the other as the outlet. In addition, the compressor is always located in the warm indoor air
stream during the heating mode, thus avoiding many problems 2.ssoci~ d with liquid refrigerant
accumulating in the col"pressor crankcase, which in current design has to be overcome by the ir~ llation
of a crankcase heater and~or by insulating of the compressor.
Several different types of reverse air cycle heat pumps have been designed also, although none of them
feature the dual capability of the evaporator to switch from a large surface area mode to a multiple row
evaporator mode.
To aid in ~,~,ulaining the various air circuits inside the machine, I will resort to a series of schematic air
flow diagrams, which will show the positioning of the air valves for each of the six poss.~ modes of
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operdlion. It should be kept in mind that the evapordt~,r will always be a source of cooled air, while the
condenser will always be a source of heated air.
Items are only identified in figures 1, 2 and 6 to preserve the clarity of the drc.~ gs.
Fiq. 1 - Heating Fiq. 2 - Fresh air exchange (heating mode~
Fiq 3 - Cooling Fia. 4 - Fresh air exchange ~cooling mode)
Fiq. 5 - De-humidifying Fip. 6 - D~l~Jsli"g
Fiqure 1 shows the unit in the heating mode. Valve ~6) is posilioned to allow condenser fan (3) to draw
indoor air through intake opening (11~ to be discl)arged through the condenser (7), picking up heat in the
pr.,cess; the air is then directed by air vaive (~3 through indoor air discharge (12) back into the condilioned
space (1). At the same time the t~,vo valves (8) are posilioned to allow outdoor air to be drawn through
opening ~9) by fan (4) and discharged through the evdpor tvr assembly (2) in its large e~,~por~ling surface
mode, and back outdoors through opening ~10).
Fiaure 2 depicts the fresh air e~Pchange mode with pre-heated outdoor air. Compared with figure 1 only
the orier~taLion of air valve (6) has changed for this function. Outdoor air is drawn in by condenser fan (3),
passed through condenser (7) where it is heated and discharged indoors (1) via opening (12). The
ev~por ~ - blower ~4l, picks up indoor air through opening (11), passes it through the evapor~h r (2) in the
large evaporating surface configuration and discharges the air to the outdoors via opening ~10). In this mode
of oper~Lion fresh and prehea~d outdoor air is thus introduced into the living space and stale indoor air
exhausted, utilizing the latter in a heat exchange mode with the evaporator, thus realizing a substantial
energy recovery.
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Fi~ure 3 shows the air flow conditons in the cooling mode. Valves ~5~ and (6~ have changed orient~tion,
now allowing the condenser fan (3) and the condenser (7) to form an outdoor air circuit through the openings
~9) and (10). The evaporator air circuit picks up indoor air through opening (11) to be passed through the
ev~po,dlur either in the multi-row or large surface configuration depending on the humidity level of the
indoor air. Cooled air is returned to the indoors through opening (12~.
Fiqure 4 depicts the fresh air excllange mode with outdoor air being cooled down and introduced into the
indoor space (1~. The air circuit is identical with figure 3 except that valve (6) is positioned to allow the
evdpor~tur fan (4) to pick up outdoor air through opening (9) this air is being cooled down by the e~porator
(2~ in the multi-row or large suRace configuration depending on outdoor air humidity levels and discharged
indoors through opening (12). The condenser fan (3) in the ",eanli",e picks up indoor air through opening
(11) and discharges same to outdoors through opening (10). Fresh outdoor air is thus cooled and de-
hun,.Ji'ied while stale indoor air is exhausted. At the same time the condenser utilizes relatively cool indoor
air to condense the ,~f,igerar,l consequently realizing an energy recovery in this mode also.
Fi~ure 5 shows the unit in the de-humidifying mode. The two outdoor air shutoff valves ~8) are now
closing off the outdoor openings ~9) and (10) and at the same time opening up a bypass pa~sage allowing
air to communicate b~,h~een the left and right sides of the unit. Valve ~6~ is position~ so that the
evaporator fan (4) picks up indoor air through opening ~11) and passes it through the e~,~pordlor in the multi-
row configuration for maximum de-humidifying e~fect. The cooled and de-humidified air is directed through
the bypass passage, picked up by the condenser fan ~3) reheated by the condenser (7) and d;~ harged
indoors through opening (12). This process is continued until the desired humidity level is reached.
Fiaure 6 represents the air flow during a defrost cycle. Depending on the outdoor humidity and
temperature con.lilions, the evaporator will accumulate frost on it's fin surfaces and if no preventive
measures are taken, the air flow through same will be blocksd colllp!~ -!y. Every heat pump requires
some means for regularly def,u~ting the evapo,ator. The reversing refrigerant model swit~ hes to the cooling
mode for this purpose, now turning the outdoor evaporator into the condenser the heat of condensation
melting the frost. This works satisrd- torily, but with the drawback that the indoor condenser now becGmes
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the evaporator cooling down the air that enters the living space and auxilliary heaters have to be actuated to
make up for this heat loss. My design takes care of this problem by d~energizing the cGn,pressor, closing
off the outdoor air openings ~9&10) placing the air valves (~3 and (6) in the positions indicated and
actiYating an electric defrost heater (13l. A compl_~ly isolated internal air circuit is thus formed in which
heated air can be circulated by evaporator fan ~4) until the evaporator ~2) has been completely def,osted.
BRIEF DESCRIPTION OF DRAWINGS 7 THROUBH 11
Fi~ure 7 is a top view of the ev-~por~lur col~npail".e"l with the ev~pordluor ass~l"bly placed in the multiple
row configuration.
Fiqure 8 shows the same conlpa,l ,.ellt with the evdpordtur placed in its large surface area configuration.
Fiqure 9 depicts the upper compartment with the top cover of the unit removed. The unit is shown with the
air valves positioned in the heating mode.
Fiaure 10 depicts the upper compartment with the top cover of the unit removed. The air valves are
positioned for the de-humidifying mode.
Fi~ure 11 is a side view of the entire unit with the panel on the co"lpressor side removed.
DESCRIPTION OF THE PREFEP<RED EMBODIMENT
A multiple-function heat pump consi~li"g of two supe",.,posed rectangular co,.,paill,lenb the lower
one housing a multiple-mode evapordLur assembly ~2) the evaporator fan and motor (4) while the upper
cG",pa,l,nent cori~~ ,s the col"p,~:ssor (19) condenser ~7) condenser fan (3~ and the various air change-
over valves is shown in figures 7 through 11.
Fi~ure 7 depicts the top view of the evaporator compa-l-nent v~rith the upper compartment removed. The
evaporator asse,.,bly (2~ is oriented in the multiple-row configuration mode. The evaporator fan and motor ~4)
are located at the left end the air being drawn in from the upper co" ,pa, l."ent and discl aryed through baffle
(14) across the evaporator assembly (2). The rotating base ~17) of this asser"bly has posilioned the
evapor~lur slabs such that a seal is formed with the two fixed bames (15) and the Iwo pivoting baffles (16).
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Air discharged from the evapor;~lùr fan ~4) thus traverses each evaporator slab in turn and is discharged to
the upper coi"pailr"~nl through the interior opening (18~.
Fi~ure 8 shows the same cornpall~"er,l with the evdpor~lor assembly ~2~ now positioned in the large
evaporating surface mode. The base of the assembly ~1n has been rotated 90 so that the ends of two
slabs seal with the t~,vo fixed baffles (15~. The two pivoting baffles (16) are now aligned with the sides of the
compartment. Air discharged by the fan (4) will pass through all slabs at the same time before being
discharged through the interior opening (18) to the upper compartment.
Fi~ure 9 is a view of the upper co~npa,ln.er,L shown in the heating mode v~fith the top cover removed
and displaying all the items contained therein including a partial view of the lower compartment specifically
the evdporalur fan & motor (4) and a section of the rotating base ~17~ of the evapordtor assembly.
The central section of this compartment houses the compressor (19) the condenser ~7) and the
condenser fan (3). This fan is driven by the condenser fan motor ~20) the latter being located on the opposite
side of bulkhead (21). Air discharged from the condenser fan (3) traverses the condenser (7) and is directed
onto the pivoting condenser outlet valve (5) the latter one forcing the air to exit the unit through the indoor
discharge opening ~12). On the intake side of the condenser fan air is drawn in through the indoor inlet
opening (11~ and directed by the pivoting evapG.dlur inlet valve ~6) to the condenser fan (3).
The two outdoor air shutoff valves (8) are opening up the outdoor inlet ~9) 8, outlet (1û) openings
allowing the evapordtor fan (4) to draw in outside air through opening (9). After having been passed through
the ev~pordlur assembly this air is directed through the interior opening ~18) bet~,veen the lower and upper
con .pa, I"~ents towards the condenser outlet valve (5) and the outdoor outlet opening (10) to the ouWoors.
Fi~ure 10 is the same view as figure 9 with the two air valves (5) & (6) now ,eosilioned for the de-
hurnidifying operation. The two outdoor shutoff valves (8) now closing off the two outdoor openings (9) &
~10~ are at the sarne time opening up a passage between the left and right sides of the upper co. ",~,a, L" ,er,l.
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This pass~ge also houses the motor (20) for the condenser fan 13). The unit is thus cGmpl~tcly isolated from
the outdoors. The evaporator inlet valve (6~ allows the evaporator fan (4~ to draw in indoor air through indoor
inlet opening (11~. After passing through the evaporalur assembly in the de-humidifying mode, the
conJilioned air is passed through interior opening ~18) and directed by air valve [5) through the bypass
pacsage to the left side of the compa,L.nent. The ev~por~tur inlet valve ~6) directs the air to the condenser
fan (3), the latter pushing it through the condenser (7) from where it is discl~ar~ed via the condenser outlet
valve ~5) and indoor outlet opening (12) to the indoor space. The de-h~",idiried air is thus reheated by the
condenser and this process is continued until a s~ c.~ory humidity level is reached.
Fi~ure 11 is an elevational view of the entire unit with the cover on the col"pressor side removed. The
upper and lower compa,l"~eu~ are clearly visible. The evapor~k,r assembly ~2) is shown in the large surface
area mode with one pivoting baffle ~10) shown parallel to the side of the unit. The flexible tubing (22)
connecting the evaporator assembly (2) to the compressor l19) is located directly above the evaporator
assembly.
The upper compartment shows the condenser fan (3), compressor (19) condenser (7), the
evaporator inlet valve (6) and the condenser outlet valve (5). The opening between the upper and lower
co",pa,l.nents on the evaporator discharge side is shown by (18). The defrost heater ~13) is located in the
dischdrge air stream of the e~poralur assembly.