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Description  |
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FIELD OF INVENTION
This invention relates to solar heating and cooling and more particularly
to solar collection and storage by passive means.
BACKGROUND OF INVENTION
Since 1973, the rate of energy inflation has often exceeded the rate of
general inflation. This fact increasingly affects the home-ownership
ability of most individuals and families. There are no easy solutions to
the "energy crunch". The supply of fossil fuels is diminishing. Nuclear
plant construction and operation costs have increased greatly. Available
biomass could be converted into concentrated fuels, but there is a low
efficiency of conversion. New and economical technological
solutions--photovoltaics, wind powered generators, ocean tidal generators,
thermal systems, alternative fuels and other sources of energy--appear to
be years in the future.
In view of the above, the uses and possible uses of solar energy are
receiving more and more attention. The true potential of solar energy
cannot be determined until many different factors are evaluated. These
factors include such things as climatic conditions, outside temperatures,
speed and direction of winds, topography, the amount of radiation, azimuth
and altitude, shading, solar access, the sun's path, community acceptance,
etc.
Assuming that a reasonable potential for solar heating and cooling are
available, overall energy savings and the cost of achieving these savings
can be determined as follows: First, evaluate the total heating
requirements. Next determine what percentage of these requirements can be
met by any particular solar collector with or without a complete storage
system. Then analyze the overall cost of any proposed solar system
considering actual energy savings, as well as dollar savings, when
compared to conventional or alternative heating methods.
For example: The average daily winter space-heating requirements for a
typical house in Raleigh, N.C., are about 2.32 therms or 23,200 BTU's
(British Thermal Units) per day. At this same location, the average Jan.
BTU's per square foot/day are 867 on a horizontal surface and 945 for a
vertical surface. At the optimum space-heating-collection angle for
Raleigh (approximately 45.degree.), an average of 1,282 BTU's sq. ft./day
are available.
A good 60 square foot active solar collector will cost from five to six
thousand dollars. Such an active unit will collect some 650 to 800 BTU's
sq. ft./day. An efficient water or rock storage system--or "phase change"
storage material--will cost an additional four to seven thousand dollars.
If properly constructed, these systems can store 95% of the heat
collected. Any of these systems have a daily potential of 45,600 BTU's (60
sq. ft. times 800 BTU's times 95%), or nearly two days' heating supply.
When there are two or more consecutive winter days with cloud cover,
space-heating will have to be provided by a back-up system. Given total
cost of collectors, storage, and back-up heating, an active solar design
does not appear to be cost-effective in terms of 1983 dollars.
If solar space-heating is to pay for itself in today's economy with its
high interest rates, people have begun to think in terms of direct solar
gain. Although many experimental structures have been built, adequate
passive heat storage capacity as well as adequate insulating means to
prevent heat loss during non-solar periods have plagued the industry and
has made passive solar structures something less than completely
desirable.
BRIEF DESCRIPTION OF INVENTION
After much research and study into the above-mentioned problems, the
present invention has been developed to provide an efficient and
economical means of passively solar heating and cooling.
The above is accomplished by making the entire roof a passive collector.
The mass of the house (brick walls and tile floors over a concrete slab)
act as a thermal storage medium. The whole roof is glazed and oriented at
45.degree. so that about three to four hundred BTU's sq. ft./day are
collected in Jan. at, for example, Raleigh, N.C. This is for single
glazing. Use of double glazing will increase collection to not less than
five hundred BTU's sq.ft./day. With solar radiation striking most of the
floor and the surface of all south-facing walls, some 50% of the heat
collected is stored. Good quality, high-density masonry will release this
heat slowly at the rate needed to maintain internal house temperatures at
approximately 68.degree. to 73.degree. F. during winter. A single-glazed
area of 40 to 60 feet has the potential to collect 960,000 BTU's/day while
storing about 480,000 BTU's/day. This is adequate to provide several days'
heating requirements if an insulated ceiling (R-20 or better) is used to
prevent heat loss during hours when solar radiation is not available.
Since insulated curtains, insulated shutters, and other devices now
available to reduce heat loss from skylights and windows, are too
expensive and too impractical for use on an entire ceiling, a new solution
in the form of ceiling doors has been found to economically make the
entire structure a passive collector.
Solar cooling is accomplished via passive means such as the chimney effect
whereby cool night air is drawn across the floor and walls to replace hot
air escaping, by natural convection currents, through ceiling and ridge
vents. The mass of the house, cooled by the previous night's air,
generally reduces inside temperatures 15.degree. to 25.degree. F. when
compared to outside temperatures. Venting must be halted during the summer
daytime to deter entry of the hotter outside air.
In view of the above, it is an object of the present invention to provide
both a glazed ceiling and a glazed roof to facilitate solar collection on
the entire mass of the structure being heated.
Another object of the present invention is to provide for masonry storage
walls in efficient locations for passive solar storage.
Another object of the present invention is to provide glazed east-west
internal walls to allow nearly complete solar access to floor areas.
Another object of the present invention is to provide movable, heavily
insulated doors over the glazed ceiling to provide direct solar access to
the floor and walls of the structure when open on a winter day and to
provide insulation when closed on a winter night.
Another object of the present invention is to allow utilization of
insulated ceiling doors to reflect heat and provide shade when closed on
summer days and to speed outward radiation of internal heat when open
during summer nights.
Another object of the present invention is to provide efficient ceiling and
ridge or other vents to create a solar chimney effect on summer nights.
Another object of the present invention is to provide an additional
isolated gain system in the form of a greenhouse to increase the
efficiency of thermal storage of the masonry walls.
Another object of the present invention is to provide automatically
operated insulated doors over the ceiling of a solar structure.
Another object of the present invention is to provide an additional heat
storage/insulation buffer for protection against winter winds from the
north.
Other objects and advantages of the present invention will become apparent
and obvious from a study of the following description and the accompanying
drawings which are merely illustrative of such invention.
BRIEF DESCRIPTION OF FIGURES
FIG. 1 is a plan view of a typical building structure utilizing the passive
solar features of the present invention;
FIG. 2 is a sectional view taken through lines 2--2 of FIG. 1;
FIG. 3 is a sectional view similar to that shown in FIG. 2 illustrating the
collection of solar energy;
FIG. 4 is a sectional view taken through lines 4--4 FIG. 2;
FIG. 5 is a sectional view taken through lines 5--5 of FIG. 3;
FIG. 6 is a somewhat schematic representation of the operating means for
the ceiling doors with the same in closed position;
FIG. 7 is a somewhat schematic representation of the operating means for
the ceiling doors with the same in open position; and
FIG. 8 is an enlarged view of the ceiling reflector portion of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
With further reference to the drawings, the improved structure heating and
cooling system of the present invention, indicated generally at 10,
includes high density masonry interior heat storage walls 11 and 12 and a
high density masonry heat storage floor 13.
The structure 10 of the present invention is oriented with wall 14 being on
the north side, and preferably heavily insulated, and at least 6" thick.
Along the southern wall 15 of the present invention is provided a glazing
such as Qualex polycarbonate or similar commercially available material.
Also either single or double glazing can be used, it of course being
recommended that where cost effective, such as in colder climates, that
doubling glazing be used.
The east and west walls 17 and 18 of structure 10 are more or less standard
in configuration and construction.
The roof of structure 10 is composed of a northerly disposed roof 19 and a
southerly disposed roof 20. The north roof is constructed of standard wood
or steel trusses 21 supported by standard wood or steel stringers 22 and
includes sheet metal or other suitable covering 23.
The southern roof 20 is constructed from standard wood or steel trusses 24
supported by standard wood or steel stringers 25. Steel is suggested due
to the excessive drying, and strength reduction, of wood members when wood
is repeatedly exposed to direct sunlight and prolonged temperatures in
excess of 150.degree. F. The roof covering 26, however, is formed from a
glazing material similar to that indicated at 16 although it of course is
only necessary to have one layer at this location.
Fixed ceiling insulation 27 is provided adjacent the north wall 14 and
above storage wall 12. The portion 28' of this last mentioned ceiling
insulation overhangs into sun space or sun room 29 to shade heat storage
wall 12 during the summer months when the sun is at a high azimuth.
Double glazing 30 is provided over opening 31 running east/west along the
ceiling of structure 10. An insulated concave reflector 32 is provided
which, when opened by means such as pulley 33 and line 34, will reflect
sun rays on the north side of heat storage wall 11 as can clearly be seen
in FIG. 3, and yet, when in the closed position shown in FIG. 2, will
prevent heat loss from radiating through glazing 30.
Extending between opening 31 and fixed ceiling insulation 28 is an opening
33 having double glazing 34 covering the same. A plurality of insulated
ceiling doors 35 are hingedly mounted at 36 to ceiling trusses 37.
To open the ceiling doors 35 a means such as that illustrated in FIGS. 6
and 7 can be provided. The form of door openers provided includes a motor
38 with a take up reel 39 operatively associated therewith. A static line
40 is connected to the take up reel in the normal manner of such devices.
The line 40 is then trained over pulleys 41 and 42 and is connected at its
opposite end to static weight 43 which maintains tension on the system.
Opening lines 44 and 45 are connected at one end to one of the respective
ceiling doors 35 on the edge opposite the hinge 36. The other end of the
opening lines are connected to static line 40 after being trained over
pulleys 46 and 47 respectively.
As illustrated in FIG. 6, when the take up reel 39 is unwound against the
force of weight 43, lines 44 and 45 will allow ceiling doors 35 to close.
Since these doors are heavily insulated they will effectively insulate
opening 33.
Whenever it is decided to allow solar rays to enter the structure 10 of the
present invention, the motor 38 is activated to motivate take up reel 39
which pulls static line 40 and its connected opening lines 44 until the
doors are in the position shown in FIG. 7. Once this position is reached
the motor is turned off either manually or by way of a limit switch (not
shown).
The interior walls 50 of structure 10 which are not of the heat storage
type include glazed portions 51 so that solar rays can pass therethrough
to reach the nearby heat storage walls and floors as will hereinafter be
described in greater detail.
Ceiling vents 48 are provided through ceiling glazing 34 and are hinged at
49. It should be noted that these vents are located adjacent heat storage
wall 11.
During summer nights when it is desired to remove as much heat from the
structure 10 as possible, the ceiling vents 48 are opened as are the
ceiling doors 35 as hereinabove described. Also upper and lower vents 52
and 53 through heat storage wall 12 are opened as are vents 54 in the
interior walls 50. Likewise roof vent 52 is opened which creates a chimney
effect with natural convection currents causing excessive heat to be
expelled through such roof vents 52 as cooler ambient air is drawn in from
the outside of the structure 10 and passed through and over the heat
storage walls and floors to remove heat therefrom and to cool the same
down in preparation for the next day.
The above described venting is, of course, halted during summer daytime
hours to deter the entry of ambient air which is hotter than that inside
the structure 10.
The floor plan shown in FIG. 1 illustrates how the heat storage walls 11
and 12 and the heat storage floor 13 as well as the interior glazed walls
50 can be operatively arranged relative to each other. It is to be
understood, of course, that any number of other interior arrangements can
be used while still utilizing the inventive concepts of the present
invention.
From the above it can be seen that the present invention provides a
relatively simple and yet highly efficient passive structure heating and
cooling system which requires the use of practically no energy source
other than natural solar energy.
The present invention, may of course, be carried out in other specific ways
then those herein set forth without departing from the spirit and
essential characteristics of the invention. The present embodiments are,
therefore, to be considered in all respects as illustrative and not
restrictive, and all changes coming within the meaning and equivalency
range of the appended claims are intended to be embraced therein.
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