Robert
CUPPETILLI
Heating System
Heating System
Heating
up: Inventor says system ‘a gold mine with no end'
by Darrell Clem
by Darrell Clem
Canton inventor Robert Cuppetilli has received a patent for a
secondary heating system he says will sharply reduce energy
consumption, slash customer bills and create thousands of jobs
for companies that install it.
“This is like a gold mine with no end in the bank,” Cuppetilli, 72, said, sitting in a Canton home where he already has installed the new system.
A consultant and former demolition business owner, Cuppetilli has enlisted partners and formed Sunrise Mechanical Inc., in hopes of marketing what he calls an industry-changing creation that has prototypes for natural gas, propane, fuel oil and electric heating systems.
He also has a separate patent pending for a secondary cooling system he says will dramatically curb energy usage and reduce consumer bills.
Cuppetilli has compared his energy usage and customer bills with those of friends and neighbors who don't have the secondary heating system, and he has kept charts to show the results.
Last December, a Plymouth woman who has a home similar in size to Cuppetilli's 5,875-square-foot house had a utility bill of $631 compared to his $192, even though she kept her temperature setting at 62 degrees compared to his 71 degrees.
Cuppetilli has compared several homes with similar results. Joe Barone, a business partner and attorney, has been impressed by the results.
“The numbers are there, and they're quite phenomenal,” he said. “I think he's got something here.”
Cuppetilli estimates his invention can reduce heating costs by 67 percent or more. He hopes to secure bids from companies for the exclusive right to manufacture and distribute the secondary heating system.
Essentially, the heating system operates in supplemental mode to carry water from a water heater to the heat exchanger within an air passage in the furnace. Air within the air passage passes through the heat exchanger and is heated from the water. Then, the water returns to the water tank.
Meanwhile, a supplemental thermostat connected to the system controls an air circulator for the furnace without requiring the furnace to be activated. The furnace will turn on and heat the air only if the supplemental mode isn't sufficient to maintain the desired temperature.
Cuppetilli also uses coils and soapstone, which retains heat for 48 hours, for the system that gravity-feeds heat through his house without requiring much work from the furnace. A thermostat for the secondary heating system is set higher than the one for the furnace.
“What controls this whole thing is the thermostat,” Cuppetilli said, adding later, “The only thing I really use off the furnace is the blower. I figure I'm saving about 67 percent on my heating bill.”
It sounds complicated, and it is. Cuppetilli concedes he has spent hours explaining his invention to industry insiders. Yet, he seems confident it works — and Barone and others say he has the statistics to show it.
If he gets his invention marketed, Cuppetilli said the system could be installed without affecting a furnace's warranty.
Cuppetilli has sought bids from 29 furnace companies, and he would get royalties. He said utility companies, which stand to lose revenue, “don't want to see this.”
Even so, he said his invention could create thousands of jobs in an economy that sorely needs them. Moreover, he said he will dictate that all parts used for installation are made in America.
“I want to keep the work here,” he said.
“This is like a gold mine with no end in the bank,” Cuppetilli, 72, said, sitting in a Canton home where he already has installed the new system.
A consultant and former demolition business owner, Cuppetilli has enlisted partners and formed Sunrise Mechanical Inc., in hopes of marketing what he calls an industry-changing creation that has prototypes for natural gas, propane, fuel oil and electric heating systems.
He also has a separate patent pending for a secondary cooling system he says will dramatically curb energy usage and reduce consumer bills.
Cuppetilli has compared his energy usage and customer bills with those of friends and neighbors who don't have the secondary heating system, and he has kept charts to show the results.
Last December, a Plymouth woman who has a home similar in size to Cuppetilli's 5,875-square-foot house had a utility bill of $631 compared to his $192, even though she kept her temperature setting at 62 degrees compared to his 71 degrees.
Cuppetilli has compared several homes with similar results. Joe Barone, a business partner and attorney, has been impressed by the results.
“The numbers are there, and they're quite phenomenal,” he said. “I think he's got something here.”
Cuppetilli estimates his invention can reduce heating costs by 67 percent or more. He hopes to secure bids from companies for the exclusive right to manufacture and distribute the secondary heating system.
Essentially, the heating system operates in supplemental mode to carry water from a water heater to the heat exchanger within an air passage in the furnace. Air within the air passage passes through the heat exchanger and is heated from the water. Then, the water returns to the water tank.
Meanwhile, a supplemental thermostat connected to the system controls an air circulator for the furnace without requiring the furnace to be activated. The furnace will turn on and heat the air only if the supplemental mode isn't sufficient to maintain the desired temperature.
Cuppetilli also uses coils and soapstone, which retains heat for 48 hours, for the system that gravity-feeds heat through his house without requiring much work from the furnace. A thermostat for the secondary heating system is set higher than the one for the furnace.
“What controls this whole thing is the thermostat,” Cuppetilli said, adding later, “The only thing I really use off the furnace is the blower. I figure I'm saving about 67 percent on my heating bill.”
It sounds complicated, and it is. Cuppetilli concedes he has spent hours explaining his invention to industry insiders. Yet, he seems confident it works — and Barone and others say he has the statistics to show it.
If he gets his invention marketed, Cuppetilli said the system could be installed without affecting a furnace's warranty.
Cuppetilli has sought bids from 29 furnace companies, and he would get royalties. He said utility companies, which stand to lose revenue, “don't want to see this.”
Even so, he said his invention could create thousands of jobs in an economy that sorely needs them. Moreover, he said he will dictate that all parts used for installation are made in America.
“I want to keep the work here,” he said.
US2009078783
SECONDARY HEATING AND COOLING SYSTEM
SECONDARY HEATING AND COOLING SYSTEM
Abstract -- A heating and cooling system operates in a supplemental heating mode or a supplemental cooling mode. In supplemental heating mode, the system carries water from a hot water supply of the water heater to a heat exchanger within an air passage in the furnace to heat the building. In the supplemental cooling mode, the system carries cool water from a cool water storage tank to the heat exchanger within the furnace to assist in cooling the building.
BACKGROUND OF THE INVENTION
[0002] This invention relates to a heating system and cooling system. More particularly, this invention relates to a system for supplementing a main heating system and main cooling system.
[0003] Conventional heating systems for homes generally include a water heater and a furnace. The furnace typically provides hot air to warm the interior temperature of the house while the water heater provides hot water for the household. An air conditioner provides cool air to the building. The energy requirements of the furnace are substantially greater than the energy requirements of the hot water heater. In addition, water temperatures are less affected by environmental changes than air within a house.
[0004] An apparatus and method for supplementing a furnace to heat a building and an air conditioner to cool a building while decreasing overall utility costs is needed.
SUMMARY OF THE INVENTION
[0005] A heating system operates in normal and supplemental modes to increase system efficiency and reduce overall cost.
[0006] A heating system for use in heating a residential dwelling includes a furnace and a water heater. In supplemental mode the system carries water from the hot water supply from the water heater to a heat exchanger within an air passage for the furnace. A water return passage returns the water from the air passage back to the water heater. Air within the air passage passes through the heat exchanger and is heated from the water within. The water then returns to the water tank through a water return passage.
[0007] A supplemental thermostat is connected to the system to control an air circulator for the furnace without requiring the furnace to be activated. In supplemental mode the air circulator operates at a reduced speed compared to the speed when in normal mode such that, the system is continuing to warm the air enough to maintain the temperature without cycling on and off. A main thermostat, for the furnace, would preferably be set at a lower desired temperature than the supplemental thermostat. Thus, the system will only operate in normal mode if supplemental mode is not sufficient to maintain the desired temperature.
[0008] A cooling system for use in cooling a residential dwelling includes an air conditioner and a holding tank. In supplemental mode the system carries water from the cold water supply from the holding tank to a cooling coil. A water return passage returns the water from the cooling coil back to the holding tank. There is soapstone in the holding tank to aid in keep the water cool.
[0009] These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a schematic illustration of an example heating system of the present invention.
[0011] FIG. 2 is a schematic illustration of an example cooling system of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0012] A heating and cooling system 10 (or "HVAC system") is shown schematically in FIG. 1. The system 10 is preferably for use in heating a home or other residential dwelling. The system 10 includes a furnace 12 and a water heater 14. The furnace 12 and water heater 14 may operate on natural gas, electricity, oil or any available energy source. The furnace 12 has a thermostat 16 to control furnace operation and a control line 18 to connect the thermostat 16 to the furnace 12. The thermostat 16 is mounted within the house remote from the furnace 12 in an easily accessible area to the user. The system 10 may also include an air conditioner coil 20 (condenser) attached to the furnace 12, so that the system can provide hot and cool air for the home. An air passage 22 extends from the furnace 12 to carry the heated or cooled air (airflow indicated with arrow A) through the home.
[0013] An air circulator 24 incorporated in the furnace 12 controls the airflow through the air passage 22 and includes a control 26 to control the volume of air that is circulated through the home. Typically the air circulator 24 includes a fan 28. The speed of the fan 28 is set by the control 26 which receives input from the thermostat 16 to turn the fan 28 on or off or adjust a variable speed.
[0014] The water heater 14 includes a cold water supply 30 leading into a water tank 32 and a hot water supply 34 leading from the water tank 32. Water, indicated by arrow W, from the ground supply enters the water tank 32 through the cold water supply 30. The water is heated within the water tank 32 and exits through the hot water supply 34 to be distributed at desired locations throughout the house. The water heater 14 also includes a water tank drain valve 36. The water tank drain valve 36 is normally used to drain water from the tank 32 during maintenance or repair. During typical operation of the water heater 14 the water tank drain valve 36 is closed to retain the water within the water tank 32.
[0015] During normal system 10 operation the furnace 12 receives a control input from the thermostat 16 based upon the desired interior temperature of the home and the actual interior temperature of the home. When the difference in temperature has reached a predetermined level the system 10 is activated to either warm or cool the air. The air is distributed through the home through the air passage 22 until the thermostat 16 senses the actual interior temperature is the same as the desired interior temperature. Activating the furnace 12 requires power to heat the air and to activate the air circulator 24 to distribute the air. The fan 28 may have one operating speed or may be variable speed, and is either rotating or stationary.
[0016] When difference between the actual home temperature and the desired home temperature is large enough to require heating the home, but not large enough to require the furnace 12, the system 10 operates in supplemental mode.
[0017] A water supply passage 38 carries water from the water heater 14 to the air passage 22 for the furnace 12. The water supply passage 38 is connected to the hot water supply 34 leading from the water tank 32 to the house. Thus, the water within the water supply passage 38 has been heated by the water heater 14. A water return passage 40 returns the water from the air passage 22 back to the water heater 14. The water return passage 40 preferably is connected to the water tank 32 at the water drain valve 36. The water supply passage may be connected to the water tank 32 in another manner that allows water to return to the water tank 32, but is preferably connected at a lower end of the water tank 32.
[0018] The water passes through the water supply passage 38 to a heat exchanger 42 within the air passage 22. Air within the air passage 22 passes through the heat exchanger 42 and is heated from the water within the heat exchanger 42. The water then returns to the water tank 32 through the water return passage 40. The heat exchanger 42 is preferably a water coil heat exchanger. Water coil heat exchangers are specifically designed for carrying water through the heater exchanger coils 44. The coils 44 are typically copper and aluminum, or entirely aluminum.
[0019] A supplemental thermostat 46 is connected to the air circulator 24. A supplemental control line 48 also leads to the air circulator 24. The supplemental control line 48 is separate from the main control line 18. The supplemental thermostat 46 and control line 48 allow the air circulator 24 to be controlled in supplemental mode without requiring the furnace 12 to be activated. The air circulator 24 is used to activate the fan 28 and create air flow through the air passage 22 when in the supplemental mode. In supplemental mode the fan 28 will operate at a reduced speed compared to the fan speed when in normal mode. If the control 26 for the fan 28 does not provide variable speed capability, a rheostat or other power control can be added so that the speed of the fan 28 is reduced in supplemental mode. Optionally, in some situations, the fan 28 may not be necessary in supplemental mode, as the air may circulate sufficiently purely by convection.
[0020] The supplemental thermostat 46 is set at a desired temperature. When the actual temperature drops below the desired temperature, as sensed by the supplemental thermostat 46, water is passed through the supply passage 38 to the heat exchanger 42. The thermostat sends a signal to the air circulator 24 to begin fan 28 operation. The supplemental thermostat 46 is connected to an electric supply valve 50 and an electric return valve 52. The thermostat 46 can shut off water flow through the supply passage 38 and return passage 40 when the actual temperature is the same as the desired temperature. Preferably, the fan speed 28 is set at low revolutions per minute such that, in supplemental mode, the system 10 is continuing to warm the air enough to maintain the temperature without cycling the system on and off. The main thermostat 16 would preferably be set at a lower desired temperature than the supplemental thermostat 46. Thus, the system will only operate in normal mode if supplemental mode is not sufficient to maintain the desired temperature. The system 10 could operate in both normal mode and supplemental mode at the same time. In other words, the supplemental mode continues to operate when the normal mode is switched on.
[0021] The hot water could circulate continuously through the heat exchanger 42 and the heat could circulate by convection through the house most of the time, with the furnace 12 switched on only when necessary.
[0022] By maintaining a desired temperature with the system 10 in supplemental mode, operation of the furnace 12 is reduced. The reduced operation of the furnace 12 saves on energy costs for the system 10.
[0023] Manual supply valve 54 can be used to override the system 10 and prevent water flow through the supply passage 38. Likewise, manual return valve 56 can be used to override the system 10 and prevent water flow through the return passage 40. The manual valves 54, 56 can be used to prevent water flow to the system 10 in warmer months.
[0024] In another embodiment, a separate auxiliary cooling system 67, shown in FIG. 2, can be connected to the supply passage 38 and the return passage 40 of the heating system 10 (without or without the supplementary heating system). Cold water is initially supplied by the cool water intake 66 through the fresh water inlet 59. When the air conditioner 20 turns on, the auxiliary cooling system 67 is activated. The pump 62 is connected to the main thermostat 16 (FIG. 1) such that when the air conditioner 20 is turned on, the pump 62 will begin to circulate water in the system 67 to the coil 42 above the air conditioner 20 (FIG. 1).
[0025] The system includes two shut off valves 57, one each located on the outline pipe 56 and the return pipe 61, which can be used to shut down the system (e.g. in the winter, when the supplementary heating system is being used). These valves 57 can also be used to connect the auxiliary cooling system 67 with the supply passage 38 and the return passage 40 of the heating system 10. Temperature gages 60 are located on the outline pipe 56 and the return pipe 61 to send water temperature information to the thermostat 16 (FIGS. 1 and 2). An air separator 63 is included on the return pipe 61 to increase efficiency and remove air from the system. A drain plug 65 on the holding tank 55 is connected to a water return passage 40, which drains the water in the system and the tank 55.
[0026] During the initial startup of the system 67, the water is delivered through the cool water intake 66. After the initial activation of the system, the water will remain in the system, being pumped to the secondary coil 54 through the outline pipe 56 and back to a holding tank 55 through the return pipe 61. The holding tank is preferably made of any non-corrosive material and would be well insulated. In one embodiment, the holding tank 55 is 33.7 gallons and 18 inches long by 12 inches wide by 36 inches tall.
[0027] When the air conditioner 20 is turned off, the holding tank 55 stores the water to keep it at the cool temperature. Rools of soapstone 64 are placed in the water in the interior of the holding tank, preferably four rools with two pieces of soapstone to each rool. In one embodiment, the soapstone is 17 inches long by 3.5 inches wide by 1.25 inches thick and rests on a 1.5 degree angle.
[0028] After the initial startup, the thermostat 16 switches on the pump 62 to circulate the cold water in the tank 55 through the coil 42 whenever the air conditioner 20 is turned on. This cold coil 42 in addition to the air conditioner 20 cools the home more quickly, so that the air conditioner 20 does not have to run as long, thereby saving energy.
[0029] In an alternate mode of operation, or additionally, the pump 62 could switch on whenever the thermostat 16 detects that the temperature in the home has risen above a first cooling threshold and switches the air conditioner 20 on whenever the thermostat 16 detects that the temperature in the home has risen above a second cooling threshold, higher than the first cooling threshold. When the water temperature measured by temperature gages 60 indicates that the water has risen above a threshold water temperature, then the water will not be able to provide sufficient cooling, and the air conditioner 20 is switched on.
[0030] The thermostat 16 may include a processor with software or a simple circuit for controlling the operation of the various pumps, valves, furnace, air conditioner, etc. as described above. Because the air condition 20 will run less, it may be necessary to take other steps to reduce the humidity in the home, such as adding air boosters.
[0031] Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.
US7628337
Secondary Heating System
Secondary Heating System
Abstract -- A heating system operates in supplemental mode to carry water from a hot water supply of the water heater to a heat exchanger within an air passage in the furnace. A water return passage returns the water from the air passage back to the water heater. Air within the air passage passes through the heat exchanger and is heated from the water within. The water then returns to the water tank through a water return passage. A supplemental thermostat is connected to the system to control an air circulator for the furnace without requiring the furnace to be activated. The furnace will turn on and heat the air only if supplemental mode is not sufficient to maintain the desired temperature.
BACKGROUND OF THE INVENTION
[0001] This invention relates to a heating system. More particularly, this invention relates to a system for supplementing a main heating system.
[0002] Conventional heating systems for homes generally include a water heater and a furnace. The furnace typically provides hot air to warm the interior temperature of the house while the water heater provides hot water for the household. The energy requirements of the furnace are substantially greater than the energy requirements of the hot water heater. In addition, water temperatures are less affected by environmental changes than air within a house.
[0003] An apparatus and method for supplementing a furnace to heat a building while decreasing overall utility costs is needed.
SUMMARY OF THE INVENTION
[0004] A heating system operates in normal and supplemental modes to increase system efficiency and reduce overall cost.
[0005] A heating system for use in heating a residential dwelling includes a furnace and a water heater. In supplemental mode the system carries water from the hot water supply from the water heater to a heat exchanger within an air passage for the furnace. A water return passage returns the water from the air passage back to the water heater. Air within the air passage passes through the heat exchanger and is heated from the water within. The water then returns to the water tank through a water return passage.
[0006] A supplemental thermostat is connected to the system to control an air circulator for the furnace without requiring the furnace to be activated. In supplemental mode the air circulator operates at a reduced speed compared to the speed when in normal mode such that, the system is continuing to warm the air enough to maintain the temperature without cycling on and off. A main thermostat, for the furnace, would preferably be set at a lower desired temperature than the supplemental thermostat. Thus, the system will only operate in normal mode if supplemental mode is not sufficient to maintain the desired temperature.
[0007] These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a schematic illustration of an example heating system of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0009] A heating and cooling system 10 (or "HVAC system") is shown schematically in FIG. 1. The system 10 is preferably for use in heating a home or other residential dwelling. The system 10 includes a furnace 12 and a water heater 14. The furnace 12 and water heater 14 may operate on natural gas, electricity, oil or any available energy source. The furnace 12 has a thermostat 16 to control furnace operation and a control line 18 to connect the thermostat 16 to the furnace 12. The thermostat 16 is mounted within the house remote from the furnace 12 in an easily accessible area to the user. The system 10 may also include an air conditioner 20 attached to the furnace 12, so that the system can provide hot and cool air for the home. An air passage 22 extends from the furnace 12 to carry the heated or cooled air (airflow indicated with arrow A) through the home.
[0010] An air circulator 24 incorporated in the furnace 12 controls the airflow through the air passage 22 and includes a control 26 to control the volume of air that is circulated through the home. Typically the air circulator 24 includes a fan 28. The speed of the fan 28 is set by the control 26 which receives input from the thermostat 16 to turn the fan 28 on or off or adjust a variable speed.
[0011] The water heater 14 includes a cold water supply 30 leading into a water tank 32 and a hot water supply 34 leading from the water tank 32. Water, indicated by arrow W, from the ground supply enters the water tank 32 through the cold water supply 30. The water is heated within the water tank 32 and exits through the hot water supply 34 to be distributed at desired locations throughout the house. The water heater 14 also includes a water tank drain valve 36. The water tank drain valve 36 is normally used to drain water from the tank 32 during maintenance or repair. During typical operation of the water heater 14 the water tank drain valve 36 is closed to retain the water within the water tank 32.
[0012] During normal system 10 operation the furnace 12 receives a control input from the thermostat 16 based upon the desired interior temperature of the home and the actual interior temperature of the home. When the difference in temperature has reached a predetermined level the system 10 is activated to either warm or cool the air. The air is distributed through the home through the air passage 22 until the thermostat 16 senses the actual interior temperature is the same as the desired interior temperature. Activating the furnace 12 requires power to heat the air and to activate the air circulator 24 to distribute the air. The fan 28 may have one operating speed or may be variable speed, and is either rotating or stationary.
[0013] When difference between the actual home temperature and the desired home temperature is large enough to require heating the home, but not large enough to require the furnace 12, the system 10 operates in supplemental mode.
[0014] A water supply passage 38 carries water from the water heater 14 to the air passage 22 for the furnace 12. The water supply passage 38 is connected to the hot water supply 34 leading from the water tank 32 to the house. Thus, the water within the water supply passage 38 has been heated by the water heater 14. A water return passage 40 returns the water from the air passage 22 back to the water heater 14. The water return passage 40 preferably is connected to the water tank 32 at the water drain valve 36. The water supply passage may be connected to the water tank 32 in another manner that allows water to return to the water tank 32, but is preferably connected at a lower end of the water tank 32.
[0015] The water passes through the water supply passage 38 to a heat exchanger 42 within the air passage 22. Air within the air passage 22 passes through the heat exchanger 42 and is heated from the water within the heat exchanger 42. The water then returns to the water tank 32 through the water return passage 40. The heat exchanger 42 is preferably a water coil heat exchanger. Water coil heat exchangers are specifically designed for carrying water through the heater exchanger coils 44. The coils 44 are typically copper and aluminum, or entirely aluminum.
[0016] A supplemental thermostat 46 is connected to the air circulator 24. A supplemental control line 48 also leads to the air circulator 24. The supplemental control line 48 is separate from the main control line 18. The supplemental thermostat 46 and control line 48 allow the air circulator 24 to be controlled in supplemental mode without requiring the furnace 12 to be activated. The air circulator 24 is used to activate the fan 28 and create air flow through the air passage 22 when in the supplemental mode. In supplemental mode the fan 28 will operate at a reduced speed compared to the fan speed when in normal mode. If the control 26 for the fan 28 does not provide variable speed capability, a rheostat or other power control can be added so that the speed of the fan 28 is reduced in supplemental mode. Optionally, in some situations, the fan 28 may not be necessary in supplemental mode, as the air may circulate sufficiently purely by convection.
[0017] The supplemental thermostat 46 is set at a desired temperature. When the actual temperature drops below the desired temperature, as sensed by the supplemental thermostat 46, water is passed through the supply passage 38 to the heat exchanger 42. The thermostat sends a signal to the air circulator 24 to begin fan 28 operation. The supplemental thermostat 46 is connected to an electric supply valve 50 and an electric return valve 52. The thermostat 46 can shut off water flow through the supply passage 38 and return passage 40 when the actual temperature is the same as the desired temperature. Preferably, the fan speed 28 is set at low revolutions per minute such that, in supplemental mode, the system 10 is continuing to warm the air enough to maintain the temperature without cycling the system on and off. The main thermostat 16 would preferably be set at a lower desired temperature than the supplemental thermostat 46. Thus, the system will only operate in normal mode if supplemental mode is not sufficient to maintain the desired temperature. The system 10 could operate in both normal mode and supplemental mode at the same time. In other words, the supplemental mode continues to operate when the normal mode is switched on.
[0018] By maintaining a desired temperature with the system 10 in supplemental mode, operation of the furnace 12 is reduced. The reduced operation of the furnace 12 saves on energy costs for the system 10.
[0019] Manual supply valve 54 can be used to override the system 10 and prevent water flow through the supply passage 38. Likewise, manual return valve 56 can be used to override the system 10 and prevent water flow through the return passage 40. The manual valves 54, 56 can be used to prevent water flow to the system 10 in warmer months.
[0020] Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.