Note: Descriptions are shown in the official language in which they were submitted.
CA 02740042 2011-05-10
Solar and Ambient Sourced Heat Pump System, Patent Application
Paul Joseph Geofroy Page 1 of 5
BACKGROUND OF THE INVENTION
Restaurants, recreation buildings, hotels, apartment buildings, food
processing
factories, and other such buildings have high heating loads. Whether the loads
are
domestic hot water, pools, space heating, or process heat, solar thermal
heating systems
can provide a portion of the energy with long-term payback. In climates that
do not have
strong sun year-round, these solar thermal systems under-perform the majority
of the
year, reducing energy savings and extending the payback time. Using a
combination of
solar-thermal collectors, preferably unglazed, and a heat pump, the energy
production
efficiency and number of hours of operation per year are greatly increased.
This
combination serves to increase annual energy savings, reduce installation cost
and thus
reduce payback time.
POWER POWER
UNGLAZED OPERATING RANGES OPERATING OPERATING
WITH ITHOU RANGE RANGE
GLAZED,,, HEA HEAT WITH -p,, WITHOUT
1111T....:: PUMP PUMP HEAT HEAT
PUMP PUMP
TUBE ..*..w=;.`. ...
UNGLAZED
GLAZED-.
EVAC :........... :, ...... ............
TUBE o
TFLUID-TAMB TFLUID-TAMB
Warm Sunny Day Cold Cloudy Day
Figure 1. Solar Thermal Panel Output Power With and Without Heat Pump
Figure 1 shows the advantages of cooling the fluid flowing through the solar
panels with a heat pump, and the superior performance of inexpensive unglazed
panels
during cool cloudy weather. In addition, a solar and ambient sourced heat pump
system
continues to work through the night, while systems without heat pumps are
inoperative.
A solar and ambient sourced heat pump system can take on many different
configurations. Solar thermal collectors, heat pumps, heat storage devices,
and end use
for the heat can be mixed and matched within the context of a solar and
ambient heat
pump system.
The solar collectors can be conventional glazed or solar-thermal collectors,
or
conventional unglazed solar-thermal collectors designed for heating pools, or
an array of
metal or plastic pipes with or without fins, mounted on a roof or wall, or
standing-seam
metal roofing imbedded with tubes for carrying fluid, or metal exterior wall
sheeting,
similarly imbedded with tubes. Solar radiation falling on these collectors
heats the fluid
in the tubes.
CA 02740042 2011-05-10
Solar and Ambient Sourced Heat Pump System, Patent Application
Paul Joseph Geofroy Page 2 of 5
A conventional chiller, or water-to-water heat pump cools the fluid flowing
through the pipes of such collectors. When there is no sun, the heat pump
keeps the fluid
sent to the panels below ambient temperature, and the ambient air and rain in
contact with
the panels reheat the fluid. When there is strong sun, the heat pump keeps the
fluid
temperature as low as possible to reduce heat loss to the ambient air. The
heat pump
absorbs energy in its refrigeration process, and transfers it to hot water for
any of the
previously mentioned purposes.
Another configuration uses an air sourced heat pump, which cools ambient air
drawn through pipes imbedded in standing seam metal roofing or wall sheeting.
It
transfers the energy that it absorbs to hot water or air for any of the
previously mentioned
purposes.
Often, during periods of strong sun, there is more heat energy available from
the
collectors than the heat pump can absorb. In these cases, the system
controller will
redirect the heat flow to transfer energy directly to the load or to heat
storage devices,
bypassing the heat pump. This increases the overall system coefficient of
performance,
by transferring heat without using electrical energy to run the heat pump.
The system can contain storage elements, such as water tanks or other thermal-
mass based storage devices, or energy storage using phase change material.
These storage
elements may be on the source (cold) side of the heat pump and/or on its load
(hot) side.
Figure 2 shows the power absorbed by an example solar and ambient sourced
heat pump system, supplying heat for domestic hot water. In this example,
solar radiation
supplies most of the energy during the day, and energy stored in ambient air
and rain
supplies the energy during the night. Electrical energy to run the heat pump
ends up as
heat, available to the hot water load.
AVAILABLE SOLAR AND AMBIENT POWER OVER TWO DAYS
11 A
7.00, rnb~eril,
Ssoiar
\ Rb
111
I'M
Loo
000
a 4'3 CS 3;iS <} v c, Ui 0 vn b n O In o Un !n C 0 W. O In C Ln 0 W O
t+'S W 0 ~` Y/1 N #' t M J M O M: C W r', - ti f/! - f'1
w t+5 w C4 0 Cd! %h !'~ n ,J ^=t ry f*; . ;:1 4X`i r; J v? h+ rV
TIME
Figure 2. Energy Absorbed by Solar and Ambient Sourced Heat Pump System
The energy absorbed by the system is either transferred directly to the
domestic
hot water or stored in water tanks and delivered to the domestic hot water as
needed at a
CA 02740042 2011-05-10
Solar and Ambient Sourced Heat Pump System, Patent Application
Paul Joseph Geofroy Page 3 of 5
later time. A natural gas fired boiler supplies any energy required to ensure
a firm supply
of hot water at 55 C. In the example shown in Figure 2 and Figure 3, the heat
pump can
only raise the water temperature to 50 C, so there is always some small amount
of natural
gas needed to increase the temperature to 55 C.
POWER DELIVERED TO DHW OVER TWO DAYS
Natural Gas
14,0
Solar & Ambient Systern
8.0
0,0
a u o vs ca Ã~ n e zn n cs pp u C> u, m U 0 ur c n CI
i?'7 .. la Yy ya C7 M LL` ' :Tt v=i T:r !*'1 C7 1f 1.7 wW 4"~
4 R3 a, w4 M s6 tt% C rw r~ I M to tU Y' u N n t=.w ra
1*i C~ ..i .. ..s .=P +}w. j: j 1V t'+9 r-f --+ rw r-a ?V dV
Tim
Figure 3. Energy Delivered by Solar and Ambient Sourced Heat Pump System
In climates with significant snow, solar absorbing panels that are not mounted
vertically can be covered, resulting in no absorption of solar radiation, and
reduced
conduction of ambient heat. The solar and ambient sourced heat pump system
senses this
condition through the following algorithm.
Using parameters for the solar absorbers absorption and conduction, and
measured values for insolation and ambient temperature, an algorithm in the
system
controller calculates what the panel's surface temperature should be. If the
calculation
indicates the panel surface temperature should be above 4C, and the measured
panel
surface temperature is les than 2C, and if this condition persists for more
than 15 minutes,
there is snow on the solar panels. Alternately, a temperature sensor in a
vertical black
metal plate may act as a proxy for what the panel surface temperature should
be instead
of calculating this temperature. If there is snow on the panels, the solar and
ambient
sourced heat pump system will perform a half hour snow melting cycle, in which
it
warms the panels by reversing the operation of the heat pump. The system
controller will
then repeat the test for snow on the panels, and repeat snow-melting cycle if
necessary,
and if it has enough stored energy to do so.
CA 02740042 2011-05-10
Solar and Ambient Sourced Heat Pump System, Patent Application
Paul Joseph Geofroy Page 4 of 5
SPECIFICATION SUMMARY OF THE INVENTION
The following summary refers to Figure 4 in the drawing PDF. The solar and
ambient sourced heat pump system is comprised of a controller (N), which has
inputs (P)
from all sensors and meters, outputs (Q) to the heat pump, (E) and to all
pumps and
motor controlled valves, and communication I/O (R) for external control and
monitoring;
an array of solar absorber panels, (A); a heat exchanger between the panel
fluid and the
cold water (I); a circulation pump (F) to feed panel fluid to said heat
exchanger; a motor
controlled valve (C) to block cold panel fluid from freezing water in said
heat exchanger;
a heat storage tank (B) containing water or phase change material with a low
melting
temperature; temperature and flow control valves (D) to regulate the
temperature and
rate of flow going into the heat pump source input; a water to water heat pump
(E) to
extract energy from the panel fluid; a panel pump (0) to circulate the panel
fluid; a load
circulation pump (G); a heat exchanger (H) to transfer the energy to the water
being
heated; a pressurized preheat storage tank (L) to store preheated water for
later use; a
circulation pump (K) to allow for energy transfer through heat exchanger (H)
when there
is no incoming cold water flow; a flow meter (M) on the cold water input;
various
temperature sensors (U1:7); and insolation meter (V).
With all components working together under control of the system controller
(N),
the system transfers heat through the heat pump at its maximum transfer power,
transfers
as much surplus heat as possible through heat exchanger (I) to the incoming
cold water,
and stores the remainder by transferring the energy through heat exchanger (W)
to heat
storage tank (B). The system continually transfers heat from the load side of
heat pump
(E), through heat exchanger (H), to preheat tank (L) and to the exiting
preheated water.
System controller (N) calculates the heat energy transferred to the incoming
cold
water, using information from flow meter (M) and temperature sensors (U 1),
(U2) and
(U3). The system controller (N) adjusts valves in the Temperature and flow
control unit
(D) to ensure the source input temperature (U4) is within the specification of
heat pump
(E). The system controller (N) monitors the panel surface temperature (U5) and
Panel
output fluid temperature (U6) to decide when the heat pump should operate, and
whether
or not to pass energy through heat exchanger (I). The system controller (N)
monitors the
panel surface temperature (U5), external ambient temperature (U7), and
insolation meter
(V) to decide when to melt snow off of the panels. System Controller (N)
monitors
wattmeter (T) and logs electrical power and energy use. System controller (N)
provides
information on all temperatures, flow, power, accumulated electrical energy
and
accumulated heat energy via its Human-Machine-Interface {HMI}. It also
provides
manual overriding of all automatic system operations. System Controller (N)
provides
this same information and control via its communication 1/0 to remote human
machine
interfaces.
When melting snow from panels (A), system controller (N) reverses heat pump
(E) so that it cools the water stored in preheat tank (L) and heats the panels
(A). It does
this only in conjunction with strong sunlight or high ambient external
temperatures.
