Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to energy management systems and more
particularly relates to devices and methods for automatically
controlling the heating, cooling, ventilation, lighting and other
devices in a building to provide a r-x; mllr saving of energy. The
system is particularly suitable for automatic energy management for
a school, office building or a home in which various rooms have a
somewhat known occupancy schedule or pattern throughout the year.
A large amount of energy is consumed in the operations of
heating, cooling, ventilation, lighting and other loads in a
building. Commonly, the heating and cooling operations are
controlled automatically with a thermostat or a plurality of
thermostates are provided, which initiate these operations
according to pre-set temperature limits. The thermostat is located
at predetermined central location or the plurality of thermostats
are located at predetermined locations in the building. During
winter months, the thermostat, set in the heating mode, would
commence the operation of the heating equipment when it detects
that the ambient temperature in the building has fallen below a
pre-set lower temperature limit; and it would turn off the heating
equipment when the ambient temperature in the building has reached
a pre-set upper temperature limit. In the summer months, the
thermostat, set in the cooling mode, would initiate the operation
of the cooling equipment when the room ambient temperature has
risen above a pre-set upper temperature limit, and it would
terminate the operation of the cooling equipment when the ambient
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temperature has been cooled to a pre-set lower temperature limit.
The thermostat would initiate the selected operations regardless of
whether or not the building is occupied. Since many buildings may
be unoccupied for certain periods of time, the continued operation
of the heating or cooling equipment during such unoccupied periods
would result in the wastage of a large amount of energy. Attempts
have been made to reduce the energy wastage by incorporating a
timer in the thermostat in which the timer would additionally
terminate the heating or cooling operation set back to an energy
saving mode according to certain predetermined time periods of the
day at a lower pre-set heating temperature limit or higher pre-set
cooling temperature limit when the building is expected to be
unoccupied. Such provision is practical only if a building has a
regular occupancy schedule, for example, a home in which the
residents are normally away at work during the day time, so that
the heating and cooling operations may be set back to the energy
saving mode. However, such provision may not be used in a school
building, office building or in a home in which the occupancy of
various rooms may not be regular. This drawback is somewhat
alleviated by some known control devices incorporating a sensor to
detect the occupancy of the building so as to intercept the heating
and cooling operations. Such control devices commonly are provided
with programming devices such as a touch panel with which the user
would set various functions and operating programs for the heating,
ventilation and air conditioning devices. It has been found that
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most users do not understand how to pre-set such operating
programs, resulting in the improper setting or no setting at all of
the operating programs and unnecessary wastage of energy.
It is a principal object of the present invention to provide
an energy management system which is capable of operating
selectively the heating, ventilation, air conditioning, lighting
and other energy consuming devices according to predetermined
operating programs in order to maintain a room in a building at a
desired ambient condition and to m~;m; ze energy savings.
It is another object of the present invention to provide an
energy management system which monitors the operation of heating,
ventilation, air conditioning, and various other devices to operate
in an efficient manner all year round.
It is another object of the present invention to provide an
energy management system which automatically and accurately
determines the occupancy of a room in a building to operate various
environment control devices such as heating, ventilation, air
conditioning and other devices to maintain it at a desired ambient
condition according to the detected occupancy. It provides a
precise way to detect occupancy of the room and to provide a
precise way to start preheat of the room during cold weather and to
monitor the room progress in real time.
It is another object of the present invention to provide an
energy management system which is easy to operate and requires
little understanding by the user of the technical operations of the
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system.
It is yet another object of the present invention to provide
an energy management system which is relatively maintenance free
for a long period of time.
The energy management system comprises a micro controller
means having a plurality of memory means operative to store therein
a plurality of predetermined programs for operating energy
consuming equipment. A plurality of actuating members are connected
to the micro controller means and are operative for selecting the
plurality of predetermined programs for setting desired ambient
conditions for a room in the building. Output interface circuit
means is connected to the micro controller means and is operative
to generate a plurality of output signals according to the
plurality of predetermined programs selected. An output stage
interface means is connected to the output interface circuit means
and is operative to receive the output signals therefrom. Energy
consuming equipment means is connected to the output stage
interface means and is operative by the output stage interface
means for maintaining the room in the desired ambient conditions.
A method of controlling efficient energy consumption of the
operation of heating, ventilation, air conditioning, lighting and
other equipment in a building for obtaining desired pre-set ambient
conditions in a selected room therein comprises storing a plurality
of predetermined operating program in a micro controller means,
setting the micro controlling means to operate selected ones of
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said predetermined operating programs including selecting the
desired pre-set ambient conditions, detecting the occupancy of the
room with a motion detecting means located in the room and a
contact means mounted at an entrance door of the room, the contact
means and the motion detecting means such as an infra-red beam, or
an under mat contact, or a proximity sensor cooperating to address
the micro controller means to determine the occupancy of the room
according to the operating programs for operating the energy
consuming equipment to obtain the desired pre-set ambient
conditions.
Figure 1 is a general schematic block diagram illustrating the
energy management system according to the present invention.
Figure 2 is part of an exemplary circuit diagram of the energy
management system according to the present invention.
Figure 3 is the rer-;n;ng part of the exemplary circuit
diagram of the energy management system according to the present
invention.
With reference to the drawings which show an exemplary
embodiment of the energy management system according to the present
invention, the entire micro controller based unit may be housed in
a relatively small enclosure which may be easily retrofit in
existing buildings. Like reference numerals in the various drawings
designate corresponding parts. The main functions of the system are
monitored by a micro controller 10 which may be pre-programmed for
a predetermined long period of time such as twenty years. The
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system is provided with a rectification filter 11 which can be fed
by a wide range of voltages, for example, from 16 volts to 30 volt
DC, and from 16 volts to 24 volts AC. Such provision alleviates any
problems for an inexperienced installer of the system to reverse
the polarity of the system input erroneously. The rectification
filter 11 as more specifically shown in Figure 2, is provided with
an oversized bridge rectifier 12 and capacitive filters 13
connected across its output terminals. Typically, a lAmp rating
bridge rectifier 12 is used although only 200mAmp is required. This
provision safeguards the integrity of the rectification filter 11.
The voltage from the rectification filter 11 is fed to a switching
power supply 14 through a current limiting resistor 15. The role of
the current limiting resistor 15 is to limit the current in case of
a short circuit in the system. In such event, the voltage drop
across the resistor 15 will be high and the switching power supply
will automatically limit the current according to the voltage drop
across the current limiting resistor 15.
The output of the switching power supply incorporates a fast
recovery diode 16, an inductor 17 and a large value electrolytic
capacitor 18 to smooth out the current and voltage, a low value
ceramic capacitor 19 is also included in the circuit to take care
of high frequency noise. Part of the output voltage is re-injected
to the switching power supply via a divider 20 for a precise
control of the output voltage. The filtered output supplies all the
12 volt circuitry in the system including the relays, op-amp,
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analog switch as well as part of the circuitry feeding a 5 volts
voltage regulator 14 which provides the operating 5 volts voltage
for all the logic integrated circuits. To further enhance the
reliability of the circuitry, a power supply monitoring circuit 21
is provided on the 5 volts power supply. If the voltage deviates
beyond a predetermined tolerance, the monitoring circuit 21
automatically generates a reset. The reset may also be initiated
manually by actuating a push button on the main board or by a
watchdog circuit 22 which ensures the reset functions at the
correct timing.
In common energy management systems, motion detectors are
usually employed to initiate the operations of the lighting and
heating in a building. The main drawback of such known systems is
that the motion detectors would turn off the lighting or heating
when there is not sufficient motion detected. Such motionless
condition often occurs, for example, when a person within the
sensing area remains at the same location in the room and is
seemingly motionless such as working with a computer, or when a
teacher is sitting at a desk for a relatively long period of time
correcting papers. The energy management system of the present
invention obviates the above drawback by operating a presence
detection device or other similar proximity sensor in conjunction
with a door contact. After the entrance door of a room is closed,
the presence detection device is given a predetermined period of
time, for example, 10 minutes, to detect the presence of a person
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in the room. If no presence has been detected during such 10 minute
duration, the micro controller determines that there is no person
present in the room, and it turns off the lights, external
ventilation etc in the room. Depending on the time of day and day
of the week, it will either leave the heating at the normal
setting(e.g. from 08:00 to 15:30) or set back the heating (e.g.
after 15:30). On the other hand, if the slightest presence is
detected during the predetermined time, then the fact that the room
is occupied is memorized by the micro controller 10; the system
does not take any further action as far as occupancy is concerned
until the door is opened then closed again at which time the
occupancy condition is reassessed. The micro controller 10
memorizes the status of the door contact; if the door is closed,
the micro controller 10 checks in its memory if it was closed
before; if yes, that means there is no change; if no, then it
updates its memory that the door is now closed, and resets the
timers. It functions similarly when the door opens. Since only
simple presence is to be detected, any common motion detector may
be employed. Alternatively, a mat pad, or beam detector, or
proximity sensor may be employed in place of the motion detector.
On the other hand, some known energy management systems require the
use of expensive pulse duration motion detectors which produces an
out pulse of specific duration. The motion detector 23 in the
present invention may be either an integral part of the main board
or mounted on the front panel of the unit enclosure or at a
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suitable remote location at which the motion detector senses the
entire area of the room. A plurality of door contacts 24 and/or
window contacts may be connected to a signal conditioning and pre-
processor 25 so that the inputs of these devices are filtered and
debounced and fed to the micro controller 10. These inputs also
generate a signal which is amplified in order to switch on a relay
18 to interface with an optional alarm system 27.
The temperature in the room is measured with a conventional
sensor 28 such as a thermistor probe which provides a temperature
signal to the micro controller 10 via a temperature processing
module 29 which may be an analog to digital converter. The
temperature signal from the temperature sensor 28 may be fed to a
capacitor and generating an interrupt to the micro controller 10
which measures the time it takes for the capacitor to charge to a
preset level. The capacitor is then discharged, then it is charged
by a 1% reference resistor. The micro controller 10 measures the
time it takes for the capacitor to charge to the preset level and
compares it to a table stored in its memory to arrive at a
temperature value. The advantages of this circuitry are that since
the capacitor and preset level are used to process both the
reference resistor and the probe, any error in these components
nullified. To further minimize any reading errors, several readings
are taken then averaged by the micro controller 10 before the
sensed ambient temperature value is determined by the system. One
or a plurality of temperature probes may be employed to provide
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temperature input to the micro controller 10. The plurality of
temperature probes may be remotely located from the unit housing of
the system. This arrangement allows for better and more accurate
control of the various ambient control devices of the room such as
ventilators or inside air ducts in which the return air temperature
therein may be directly sensed inside the device if desired.
An outside temperature sensor 30 may be connected to the
system to enable exact control of the heat damper and/or air
conditioning of the room as well as control of the amount of
storage on thermal storage units. For example, according to the
above, on ambient temperature rise, the modulator of the damper
would normally try to open the damper to maintain the temperature
of the room. With the outside temperature sensor 30 in place the
system may determine actually if the opening or closing of the
damper can maintain the desired ambient temperature, or if the
outside temperature is above the desired pre-set temperature such
that it would be futile to open the damper. Accordingly, the damper
would be maintained closed or in ; n; mllm position while the air
conditioning is started immediately. Similarly, the outside
temperature of the building might be l9C while the ambient
temperature might be 21C, and as soon as 30 persons come inside the
room, the temperature might rise to 24C. Instead of starting the
air conditioning, the system can react to the situation in a better
way by modulating the damper only.
A plurality of dip switches 31 and 32 are provided for
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selecting various pre-set conditions stored in the memory of the
micro controller 10 of the system. Such dip switches selection
eliminates the necessity for the user to select and vary the
conditions through front panel push buttons or similar devices.
Studies have been found that users usually do not know how
thermostat programming functions and erroneous selections often
result in inefficient operation of the energy management system.
The following functions of the micro controller 10 may be selected
with the several banks of dip switches 31 and 32 provided, as an
example:
(A) Ambient Temperature Heat: the "occupied" temperature setting
may be selected from 17 to 24 degrees C(63 to 76 degrees F) for
heating.
(B) Ambient Temperature Cool: is always automatically adjusted to
3C above the heat set point.
(C) Set Back Temperature: may be selected to turn off the system at
2, 5, 7, 10, 13, 15, or 17 degrees C(35, 40, 45, 50, 55, 60, or 64
degrees F).
(D) Start Time: to select the time at which the desired ambient
comfort temperature of the room should be reached. This could be
set in increments of one hour intervals between 06:00 to 09:00
daily.
(E) Stop Time: to select the time at which the system would reverse
to temperature set back if the room is not occupied. If the room is
occupied then the system would wait for the room to become
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unoccupied before reversing to the set back. This temperature could
be set in increments of one half hour between 15:00 to 17:00 daily.
(F) Ten Minute Door Open: this dip switch enables a function which
allows the system to turn the HVAC off if the doors and/or windows
have been left open for more than ten minutes.
(G) Door Close: 10/50 minute dip switches instruct the system to
use for example either a 10 minute or a 50 minute time delay when
the door is closed. The 10 minutes is commonly used. The 50 minute
is usually used when the door contact in not installed, in that
particular case the "motion" input of the system is jumpered to
ground while the motion is wired directly to the door input.
Therefore every time the motion detector is triggered, a 50 minutes
time delay is reset, to provide enough time to detect the occupancy
of the room and to maintain the lights and the HVAC on.
(H) Motion By: the system has the capability of knowing if somebody
enters the room (via the door contact); if the door has not been
opened by either 09:30 or 10:30 daily the system reverses
automatically to the temperature set back. If this situation occurs
two days in a row the system would determine that it is a vacation
time which has not been pre-programmed and the system would not
start the third day. This cycle is automatically reset the
following week-end or if somebody opens the door.
(I) Daylight Savings: this dip switch allows the system to
automatically adjust for daylight savings or to ignore any change
in time.
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(J) Test Fast Speed: this dip switch instructs the system to
operate in normal speed, or to switch the 10 or 50 minute door
closed timer and the one hour heat timer in a speed 60 times faster
than normal. This feature is particularly useful for installers who
can check the operation of the full system, including occupied or
unoccupied condition within minutes following installation.
(K) PWM/O-->lOV: this dip switch instructs the system to output
either a pulse width modulation or O to lOV according to the
requirement of the heater connected on the system output. The O to
lOV output is also used in conjunction with a relay board to
generate from 1 to 4 stages of heat. The pulse width modulation
(PWM) mode would for example turn the heat on for 6 seconds and
turn it off for 14 seconds. This mode as well as the O to lOV mode
allow for an extremely precise control of the temperature, always
modulating and adjusting in real time.
(L) Warm Up Multiplier: the dip switch selects the warm up
multiplier. For example, the warm up period may be multiplied to 1,
1.5, 2, or 3 times the normal period. The various warm up period
selections also compensate for the heat retaining efficiency of a
room which has very poor insulation or leaking doors or windows.
(M) 2Omin/1 hour Time Delay: this dip switch is equipped in a
system having a water management function so as to permit selection
between a 20 min. or 1 hour time delay to fill up the water tanks
of the water management system.
(N) A/C: this dip switch informs the system if the room is fitted
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with an air conditioning device. On most installations this does
not change anything but some heat sources are equipped with an
outside air damper as well as an air conditioning device.
Therefore, when the temperature rises, the system first modulates
the damper opening condition according to the temperature
differential between the desired temperature point and the selected
ambient temperature. This is also referred to as Free Cooling. If
the temperature continues to rise with such damper control only if
the room is also equipped with an air conditioning device, then the
system would close the damper to a minimum position and turn on the
air conditioning device. If there is no air conditioning device,
the damper will be maintained at its maximum opened condition.
(O) Correction: these dip switches are used to easily correct any
error in the readings of the temperature sensor, temperature
adjustment can also be made via programming.
(P) Override: these dip switches can be actuated to adjust the
normally selected ambient temperature by plus or minus 1 or 2
degrees C. These dip switches can be bypassed by providing an
override external switch which can be operated for the same
function by the user.
The micro controller 10 is also preprogrammed for all
weekends, holidays and statutory holidays forever except for Easter
which is only pre-programmed for the next 20 years (i.e. heating
will not be turned on weekends, during Easter vacation etc. Date
and time run continuously and are protected by a ten year battery
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back-up.
Additional banks of dip switches 33 and 34 may be provided to
input other control information to the micro controller 10
In order to check the memory status, or to add extra
programming, the micro controller 10 emulates any type of
programming device 35 such as a hand-held programmer, laptop
computer or other systems which can communicate with that format on
the logic level with an RS232 circuit which converts this logic
level voltage into a standard RS232 voltage level. The output of
this circuit may be supplied through an RJ11 (phone jack type) plug
36 which is directly mounted on the main board of the micro
controller 10. Additional programming for vacation days, special
days off may be easily achieved with such programming devices. The
micro controller 10 is also pre-set so that the extra programming
may be automatically erased after a particular predetermined date.
The micro controller 10 is operated with an external clock lOT
which may be composed of a crystal and two capacitors, while the
system is provided with an operating clock 37 with a 10-year back
up battery, so that the Date and Time always run continuously, even
when the system is not connected to a power supply source. Leap
years are automatically accounted for. A dip switch is provided to
allow the daylight savings hour change to take place automatically
or to be bypassed.
The watchdog timer 22 may be built in one of two ways. A
signal is either directly taken on the output of the micro
16
220~008
controller 10 or on the output of the interface circuitry 38. In
both cases it is then fed via a capacitor to a NAND gate. The
capacitor ensures that if the micro controller 10 locks up either
in "O" or "1" position a reset will happen, while the NAND gate is
used to shape the signal to a logic level square wave signal. The
output of this NAND gate goes via diode to an oscillator composed
of another NAND gate, a capacitor and a resistor. The resistor
charges the capacitor , a negative pulse coming from the previous
NAND gate (via the diode) is supposed to discharge the capacitor.
If the pulse is missing, the output of the second NAND gate goes to
a low logic level which originates a reset on the reset circuit.
The input of this reset circuit receives another signal from the
reset push button. Both signals are selected at the entrance of the
reset circuit.
The heat output of the room being controlled is maintained by
an interface heat circuitry 39 which operates to provide the
following functions:
(1) Direct heat output , one stage: a heat output is provided
at a 5V logic level. This signal is then amplified and used to
control a relay together with an LED. The contacts of this relay go
to the connector for direct interface with a relay part of the
heating system.
(2) Direct heat output, two stages: same as (1) except that
two outputs and two stages are provided.
(3) Pulse width modulation: The PWM is typically used with
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types of heaters which incorporate a solid state type of relay or
other devices which turn on and off a great number of times without
affecting their longevity.
(4) The 0 to lOV output is used either directly with 0 to lOV
control heaters, or can be interfaced to give 4 to 20mA, or other
types of analog signals, to control different types of heaters, or
it is used to drive a comparator which can generate several stages
of heat: i.e. OV to 2.5V = stage 1, 2.5V to 5V = stage 2, 5V to
7.5V = stage 3, 7.5V to lOV = stage 4.
In the case of the PWM output, the micro controller 10
generates a 5V level when the heat source must be turned on and a
OV level when it should be turned off. This 5V is then amplified to
have a more powerful output with a higher voltage. Any type of
linearization can be chosen, for example, a period of 20 seconds
with a differential of 2 degrees C in temperature linearly. If for
example the set temperature is 20C: if the ambient temperature is
18 or below, the heat will be on all the time; if it is 18.lC, the
heat will be on for 19 seconds and off for 1 second; if it is
19.5C, the heat will be on for 5 seconds and off for 15 seconds and
so on. This modulation allows for an extremely precise temperature
control.
(5) 0 to lOV: in the 0 to lOV mode, the micro controller
outputs a 0 to 1 KHz frequency proportional to a certain difference
between the ambient temperature and the required temperature. Any
type of linearization can be chosen, for example, a 2 degrees C
18
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bandwidth linearly for a O to 1 KHz change. Therefore, when the
temperature difference is 2C or more the micro controller output is
1 KHz, when the difference is O or more the frequency is O Hz and
the relation is linear between the two extremes. This frequency is
sent to a voltage to frequency converter 40, any value could be
chosen for example, OV at OHz and 5V at lKHz (linear in between).
This O to 5V is then amplified by two to give a O to lOV output,
this signal goes into a follower such as an operational amplifier,
to boost it and is passed on to the heat/damper switching circuitry
30 to initiate the heating operation. If, for example, the set
temperature is 20C; if the ambient temperature is 18 or below, the
output voltage will be lOV; if it is 18.lC, the output voltage will
be 9.5V; and if it is 19.6C, the output voltage will be 2V. This
linearization allows for an extremely precise temperature control.
The micro controller 10 also outputs to the damper through the
frequency to voltage converter 40 and heat/damper switching
circuitry 41 and a damper interface circuitry 42. The damper output
functions in one of two ways: either O to lOV or dry contact. An
output is provided by the micro controller 10 at a 5V logic level
for the dry contact circuitry. The signal is then amplified and
used to control a relay together with an indicating LED. The
contacts of this relay go directly to the PCB connector for direct
interface with an outside device.
The O to lOV output operates in a similar manner to the heat
circuit in that a O to lKHz output provides a O to lOV output.
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However, as soon as the room is occupied the damper output produces
a voltage to adjust the damper to a minimum position. When the
ambient temperature increases, the voltage produced by the
frequency to voltage converter is added to this minimum opening
voltage to modulate the damper. This modulation serves the purpose
of free cooling for allowing in more or less outside air according
to the difference in temperature between the set point and the
ambient temperature. If air conditioning is available, the damper
will modulate fully open before turning on the air conditioning,
and if the temperature continues to rise then the damper output
would go to m; n; mllm position while the air conditioning starts.
The micro controller 10 controls analog switches to redirect
the 0 to lOV output to either the heat circuit when in the heat
mode, or to the damper when it is not in the heat mode. A status
display such as an LED is provided to show the mode in which the
system is functioning.
The micro controller 10 controls the air conditioning 43
through an air conditioning interface 44 which operates in either
a single stage, if no damper is available, to turn on the air
conditioning device at the pre-set temperature, or in two stages if
a damper is available with free cooling as the first stage of
cooling in which the opening of the damper is adjusted to maintain
the ambient temperature to the pre-set temperature. An LED may be
incorporated in the air conditioning interface 44, which will be
lighted to indicate the system is functioning in the air
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conditioning mode.
The micro controller 10 sends an output signal to turn on or
off the lighting equipment in the room through a light control
interface 45 according to the occupancy of the room. An LED is
incorporated in the light control interface 45, which will be
lighted to indicate that the lighting control mode is on. For
ma~ ~ energy savings, the lighting does not follow the heating
pattern. It turns on when the door is opened, it then stays on for
as long as the room is occupied or the door is open. If the room is
unoccupied, the lighting turns off after the 10 or 50 minute time
delay as instructed by the dip switches. This enables all the
lighting to be turned off even during a break or lunch hour when
the room is empty.
The micro controller 10 provides an output signal through the
fan control interface 46 to operate a ventilation fan according to
the occupancy of the room and heat requirement. An LED is
incorporated in the fan control interface 46, which wi-ll be lighted
to indicate the fan control mode is on.
The micro controller 10 may also provide output signals to
various other loads such as a wall-mounted air conditioning device,
through an occupancy interface 47. A LED in this interface will be
lighted to indicate its operation.
Thermal storage heaters may be operated by the micro
controller 10 through a storage interface 48 which also has an LED
to indicate its operation.
2202~08
When used in conjunction with water energy management, a
solenoid valve interface 49 will receive the output signal from the
micro controller 10 to control the operation of the water supply
according to pre-set conditions. It turns on during working days
according to the start time and stays on until either room,
typically a washroom, is not occupied or until stop time. It also
comes on and stays on for the time delay duration after hours or on
non-working days. Every day at midnight this output is activated
for the duration of the time delay to fill the J-trap of the water
system so as to compensate for evaporation and to prevent hazardous
gas from entering the building.
Windows can also be wired to the system, and the
heating/cooling of the room is stopped after 10 minutes of the
window or windows being left open, as in some buildings the door
might be left open for long periods. This feature can also be
enabled or disabled with a dip switch provided.
Wiring windows to the system not only enables a closer HVAC
control if the windows are left open but also serves other purposes
such as turning the lights on if a burglar tries to enter the room.
An alarm contact output can also be interconnected with existing
alarm system.
While the preferred embodiments of the invention have been
described above, it will be recognized and understood that various
modifications may be made therein and the appended claims are
intended to cover all such modifications which may fall within the
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spirit and scope of the invention.
