Abstract:
An integrated environmental sustaining apparatus for maintaining a terrarium is adapted to simultaneously regulate temperature and deliver water droplets. The apparatus includes three major systems; a thermoelectric device, a water droplet delivery system, and a thermostat. The thermoelectric device is used to release heat or absorb heat. The water droplet delivery system includes a water pump, a water pipe and at least one water droplet dispersing device connected to the water pipe. A section of the water pipe is coupled to the thermoelectric device such that water flowing inside the water pipe will thermally communicate with the thermoelectric device. The thermostat is used to power on or off the thermoelectric device and the water pump in response to the temperature measurement inside the terrarium in relation to a predetermined temperature range determined by a low-temperature setting and a high temperature setting that can be programmed into the thermostat.

Description:
BACKGROUND OF THE INVENTION 
     The present invention, in general relates to an apparatus for maintaining desirable environmental conditions suitable for a terrarium, and more particularly, to an integrated environmental sustaining apparatus that can simultaneously regulate temperature levels inside and can deliver water droplets to a terrarium. 
     A terrarium is a man-made, enclosed habitat suitable for keeping and raising plants and animals for observation or research. Typically, the temperature and relative humidity levels inside the terrarium must be maintained within a certain predetermined range. Further, delivery of water droplets in the form of rain or mist may be required to mimic a natural environment to maintain optimum conditions for the plants and animals inside the terrarium. 
     Temperature control is achieved by either a global control mechanism or a local control mechanism. If a terrarium environment is kept inside a room, the entire room can be kept within a pre-determined temperature range by a conventional air conditioning system that can provide both heating and cooling. Air internal to the terrarium will generally reach thermal equilibrium with room air surrounding the terrarium with the aid of either natural convection or forced convection (i.e. a forced air circulation system inside the terrarium) between container walls and air inside the terrarium. Such a global temperature control system, when properly sized and controlled, works well. Since the global temperature control system keeps the room, in addition to the terrarium within a predetermined temperature range, operating cost is relatively high. More importantly, the existence or the wellbeing of the terrarium depends on the existence of the room air conditioning system. 
     Alternatively, temperature control of a terrarium can be achieved locally, independent of the room environment within which the terrarium resides. 
     One way to maintain the air temperature inside a terrarium above a predetermined low temperature setting in a cold weather is to apply one or more heat pads to one or more exterior walls of a terrarium. When heat pads are powered on, heat is transferred from the pads to the walls primarily through conduction, and from the heated walls to the interior air through natural or forced convection depending on whether there exists a forced air circulation system inside the terrarium. A thermostat is typically used to control power to the heat pads based on temperature measurements inside the terrarium by one or more temperature sensors. 
     To maintain the air temperature below a predetermined high temperature setting in warm or hot weather, cooling must be provided to the terrarium. Conventional compressor based air cooling system can be used to remove heat from inside the terrarium. Efficient delivery of cooling is typically achieved by a forced air circulation system that generally includes a fan/blower and ductwork that is thermally coupled with the cooling generating system. 
     For humidity control, since a terrarium is generally a significantly enclosed container, humidity can simply be maintained at a high level that is suitable for a terrarium as long as there is water in the container. 
     However, providing rain or mist to terrarium must be accomplished independent of temperature regulating mechanism. Typically, rain or mist is provided to a terrarium system by a water droplet delivery system driven by a water pump. Generally, the terrarium can be adapted to support an internal water reservoir that is deep enough to keep the inlet of the water pump submerged; water can be drawn from the internal reservoir to provide rain and mist. In a well-covered terrarium, there is generally very little evaporation from inside of the terrarium to the outside, and the terrarium is generally kept in an equilibrium state in terms of overall water level. As such rain or mist can be provided as frequently as needed without frequent human intervention to add water into the terrarium. 
     In summary, to maintain a terrarium, one will need a temperature regulating system which comprises one or more devices that can generate heating and cooling and, for a local temperature regulating system, an air circulating system to deliver heating or cooling air inside the terrarium. One will also need a rain/mist generating system. Typically, the temperature regulating system is controlled by a thermostat and the rain/mist generating system by a time control device, or a timer. As such, a typical terrarium maintenance system comprises at least two separate sub-systems that are controlled separately. 
     Therefore, there exists a need for an integrated environmental sustaining apparatus for terrarium systems to simplify terrarium maintenance. 
     BRIEF SUMMARY OF THE INVENTION 
     The primary objective of the present invention is to provide an integrated apparatus that can simultaneously regulate temperature to within a pre-determined temperature range and can generate and deliver water droplets to a terrarium. The apparatus has a thermoelectric device that can release heat (heat) or absorb heat (cool) depending on how the device is connected to a direct current (a.k.a. DC) power source, and a water circulation and water droplet discharging system that is thermally coupled with the thermoelectric device in such a way that the circulating water can exchange energy with the heating/cooling surface of the thermoelectric device. The integrated apparatus further comprises a control device such as a thermostat that activates or deactivates the thermoelectric device and the water circulating device simultaneously depending on the temperature inside the terrarium. 
     The various objectives and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
       The invention is described in greater detail hereinafter by reference to the accompanying drawings wherein: 
         FIG. 1  is a schematic diagram of one embodiment of an integrated water droplet dispensing and heating/cooling apparatus for a terrarium that includes plants, and animals and an internal reservoir. 
         FIG. 2  is a schematic diagram of a thermoelectric device connected to a DC power source. 
         FIG. 3  is a schematic diagram of a thermoelectric device connected to a DC power source in a reversed polarity with reference to  FIG. 2 . 
         FIG. 4  is a schematic diagram of a thermoelectric device with one side attached to a section of a water pipe and the other side attached to a heatsink and an air moving device on top of the heatsink for further enhancing heat transfer. 
         FIG. 5  is a schematic diagram of the side view of  FIG. 4  showing the cross section area of the water pipe attached to one surface of the thermoelectric device, where the cross section of the water pipe is substantially round shape. 
         FIG. 6  is a schematic diagram of the side view of  FIG. 4  showing the cross section area of the water pipe attached to one surface of the thermoelectric device, where the cross section of the water pipe is substantially elongated oval shape. 
         FIG. 7  is a schematic diagram of a section of a water pipe attached along one surface of a thermoelectric device, where this section of the water pipe is shown to be connected at both ends to water pipe sections of different outside diameter indicating that this section of water pipe and those connected to it are made of different materials. 
         FIG. 8  is a schematic of a control diagram with a thermostat controlling a power supply source to which a water pump and a thermoelectric device are electrically connected. 
         FIG. 9  is a schematic diagram of another embodiment of an integrated water droplet dispensing and heating/cooling apparatus for a terrarium that includes plants, and animals and an external reservoir. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     An integrated environmental sustaining apparatus for use in a terrarium system with an enclosure in accordance with the present invention has a plurality of systems and elements which will be identified herein below. 
     Referring to  FIG. 1  the system comprises a terrarium enclosure  10 . Inside the terrarium enclosure  10 , there are plants identified with reference numeral  11 , and animals identified with reference numeral  12 . At the bottom of the enclosure  10 , there is a mound of dirt  27  to support the plants  11  and a reservoir  13  which has a water level identified with a reference numeral  13   a . A water pump  14  has its intake end  14   a  submerged in the reservoir  13  below the water level  13   a . One end  15   a  of a water pipe  15  is connected to the outlet end  14   b  of the water pumper. Following the water flow direction inside the water pipe  15  when the water pump  14  is turned on, downstream of the outlet  14   b  there is an intermediate section  15   c  of water pipe  15  that is attached to a thermoelectric device  16 . And further downstream towards the end  15   b  of the water pipe  15  that is substantially raised above the reservoir  13  and close to the top of the enclosure  10 , there are water droplet dispersing heads  17  that are designed to deliver rain or mist when the water pump  14  is powered on. As such, when water pump  14  is powered on, water is drawn from the water reservoir  13  by the water pump  14 , and is pushed through the water pipe  15  and past the intermediate section  15   c , finally to the water droplet dispersing heads  17  to provide the required rain or mist. Further, there is at least one temperature sensor  26  that measures ambient air temperature inside the terrarium  10 . 
       FIG. 2  illustrates the details of the thermoelectric device  16 . The thermoelectric device  16  is powered by a direct current or DC power supply  18  through two wires  16   a  and  16   b . When connected to the DC power supply  18  as shown in.  FIG. 2  where  16   a  is connected to the negative terminal of the DC source and  16   b  to the positive terminal, the thermoelectric device  16  has a heat-releasing side  16   d  and a heat-absorbing side  16   c . Alternatively, when the thermoelectric device  16  is wired as shown in  FIG. 3  where  16   a  is connected to the positive terminal of the DC source and  16   b  to the negative terminal, the thermoelectric device  16  has a heat-releasing side  16   c  and a heat-absorbing side  16   d.    
       FIG. 4  shows that the side  16   c  of the thermoelectric device  16  is attached to the intermediate section  15   c  of the water pipe  15 . In order to enhance heat transfer, at least the section  15   c  of the water pipe  15  is preferably made of thermally conductive materials such as copper. To securely attach the section  15   c  to the surface  16   c  and further enhance thermal coupling, an adhesive material or an interface material  19  with enhanced thermal conductivity, such as a thermal conductive epoxy is used. In this embodiment, the water pipe  15  is made of a single material from end  15   a  to end  15   b  including the intermediate section  15   c . A variety of forms of heat dissipation means may be provided to the side  16   d  of thermoelectric device  16  for improving heat exchange efficiency. As shown in  FIG. 4  as one specific example, extended surfaces or heat dissipation fins  17  are fitted to the side  16   d , and the heat dissipation fins  17  are exposed to the ambient air outside the enclosure  10 . Moreover, an air moving device  17   a , such as a fan or a blower is provided to force airflow over and through the fins  17  to facilitate further enhanced heat transfer between the fins  17  and the ambient air. 
     When cooling of the terrarium  10  is required, the wires  16   a  and  16   b  are connected to the DC source  18  in such a way that the  16   c  is the heat-absorbing side (with reference to  FIG. 2 ), thus absorbing heat from the water flowing through the section  15   c . When heating of the terrarium  10  is required, the wires  16   a  and  16   b  are connected to the DC source  18  in such a way that the  16   c  is the heat-releasing side (with reference to  FIG. 3 ), thus heating the water flowing through the section  15   c . At the same time, the side  16   d  is the heat-releasing side. With the aid of heat dissipation fins  17 , heat released from side  16   d  is efficiently dissipated into the ambient air outside the enclosure  10 . 
       FIG. 5  shows the cross section of the section  15   c  thermally attached to the side  16   c  of the thermoelectric device  16 . The section  15   c  is shown to be substantially circular shaped. The section  15   c  is attached to the surface of  16   c  of the thermoelectric device  16  with an adhesive material  19  that is also substantially thermally conductive such that the effective contact surface area between the section  15   c  and the surface  16   c  is maximized or the heat resistance between the outer surface of the section  15   c  and the surface of  16   c  is minimized. 
       FIG. 6  shows the cross section of the section  15   c  thermally attached to the side  16   c  of the thermoelectric device  16 . The section  15   c  is shown to be substantially oval shaped that has at least one substantially flat surface  15   d  which is attached to the surface of  16   c  of the thermoelectric device  16  with an adhesive material  19  that is also substantially thermally conductive such that the effective contact surface area between the section  15   c  and the surface  16   c  is maximized or the heat resistance between the outer surface of the section  15   c  and the surface of  16   c  is minimized. 
       FIG. 7  shows an embodiment that is different from that is shown in  FIG. 4 . In this embodiment the intermediate section  15   c  and sections  15   e  and  15   f  connecting both ends of section  15   c  are made of different materials. For instance, the section  15   c  copper while  15   e  and  15   f  and the rest of the water pipe  15  are all made of plastic. 
       FIG. 8  illustrates the overall control system for the integrated environmental sustaining apparatus. The water pump  14  is powered typically by a direct current source or DC side of an AC to DC adapter  21 . The thermoelectric device is powered typically by a direct current power or DC side  18  of an AC to DC adapter  20 . Both adapters  20  and  21  are plugged into a common AC power input panel  22 . The thermostat  23  is preferably a digital thermostat that includes a display  24 , an input device  28  for inputting temperature settings, at least one actuating member  25 , and at least one temperature sensor  26 . Through the input device  28 , the thermostat  23  is adapted to receive and store one or more temperature range settings. For example, using the input device  28 , the thermostat  23  is able to receive and store a high temperature setting (e.g. 80 F) and a low temperature setting (e.g. 60 F). The temperature ranges are used control the AC power input panel  22  which in turn controls the on and off of the thermoelectric device  16  and the water pump  14 . 
     In winter time, the thermoelectric device  16  is wired as illustrated in  FIG. 2  such that the surface  16   c  is a heat-releasing side when power is provided. When the ambient temperature measured by the sensor  26  inside the terrarium enclosure  10  remains between the high (e.g. 80 F) and the low temperature (e.g. 60 F) settings, the AC input panel  22  remains inactivated, and the pump  14  and the thermoelectric device  16  remain powered off. If the ambient temperature measured by the sensor  26  falls below the low temperature (e.g. 60 F) setting, the thermostat  24  triggers the actuator  25  to activate AC power input panel  22 . The water pump  14  is powered on, drawing water from the reservoir  13  into the water pipe  15 , pushing the water past the section  15 C that is thermally attached to the thermoelectric device  16 . At the same time, the thermoelectric device  16  is also powered on, and the heat-releasing surface  16   c  becomes hot and transfers heat to the water flowing inside the pipe  15 . The water passing through the thermoelectric device  16  picks up heat and is sent to the water droplet dispersing heads  17 . Warm water droplets will heat the ambient air inside the terrarium. Ambient temperature inside the terrarium environment will rise as a result, and will eventually rise above the low temperature setting (e.g. 60 F). At that point, the thermostat  23  will trigger the actuator  25  to turn off the power supply to the AC power input panel  22 . The water pump  14  is powered off stopping water droplet dispersing, and the thermoelectric device is powered off stopping the heating process from the heat-releasing surface  16   c.    
     In summer time, the thermoelectric device  16  is wired as illustrated in  FIG. 3  such that the surface  16   c  is a heat-absorbing side when power is provided. When the ambient temperature measured by the sensor  26  inside the terrarium enclosure  10  remains between the high (e.g. 80 F) and the low (e.g. 60 F) temperature settings, the AC input panel  22  remains inactivated, and the pump  14  and the thermoelectric device  16  remain powered off. If the ambient temperature measured by the sensor  26  exceeds the high temperature (e.g. 80) setting, the thermostat  24  triggers the actuator  25  to activate AC power input panel  22 . The water pump  14  is powered on, drawing water from the reservoir  13  into the water pipe  15 , pushing the water past the section  15   c  that is thermally attached to the thermoelectric device  16 . The thermoelectric device  16  is also powered on, and the heat-absorbing surface  16   c  gets cold and draws heat from the water flowing inside the pipe  15 . The water passing through the thermoelectric device  16  releases heat to the heat-absorbing surface  16   c  and the cooled down water is sent to the rain or mist heads  17 . Cool water droplets coming out from the water droplet dispersing heads  17  absorbs heat from the ambient air achieving the goal of cooling the terrarium environment. Ambient temperature inside the terrarium environment will drop as a result to below the high temperature (e.g. 80 F) setting. At that point, the thermostat  23  will trigger the actuator  25  to turn off the power supply to the AC panel  22 . The water pump  14  is powered off stopping water droplet dispersing, and the thermoelectric device is powered off stopping the cooling process. 
     Referring to  FIG. 9  the terrarium system there illustrated is a different embodiment from that shown in  FIG. 1  and comprises a terrarium enclosure  10 . Inside the enclosure  10 , there are plants identified with reference numeral  11 , and animals identified with reference numeral  12 . At the bottom of the enclosure  10 , there is a mound of dirt  27  to support the plants  11  and an interior reservoir  13  which has a water level  13   a . A container  30  resides outside the enclosure  10  and has a reservoir  31  with a water level  32 . A water pump  14  resides inside the container  30  with its intake end  14   a  submerged in the reservoir  31  below the water level  32 . One end  15   a  of water pipe  15  is connected to the outlet end  14   b  of the water pumper. Along the water pipe  15 , there is an intermediate section  15   c  that is in thermal connection with the thermoelectric device  16  which is described in details in  FIG. 2  through  FIG. 7 . And further along the water pipe  15 , there are water droplet dispersing means  17  that are designed to provide water droplets when the water pump  14  is powered on. Moreover, to prevent water from overflowing the plants  11  inside the enclosure  10 , there is an overflow discharge pipe  33  with one end  34  located inside the enclosure  10  aligned with the water level  13   a  and another end  35  above the water level  32  of the exterior reservoir  31 . The water level  13   a  is higher than the water level  32 . As such, when water pump  14  is powered on, water is drawn from the external water reservoir  31  by the water pump  14 , and is pushed through the water pipe  15  and past the intermediate section  15   c  and the thermoelectric device  16 , and finally to the water droplet dispersing heads  17  to provide the required water droplets. The addition of water droplets into the enclosure  10  will eventually raise the water level of the interior reservoir  13  above  13   a . The excess water beyond the water level  13   a  will be drained through the overflow discharge pipe  33  into the exterior reservoir  31  thus keeping the water level inside the enclosure  10  at or below desired water level  13   a . The control of water droplet dispersing and heating/cooling of the thermoelectric device  16  is illustrated in details in  FIG. 8  and described above. 
     While the invention and exemplary embodiments of the invention have been illustrated and described in general and specific terms, it should be understood that the invention may be modified and otherwise embodied in still other forms, including but not limited to all forms which are obvious variants of or equivalent to those disclosed. 
     The preceding descriptions are by way of example and are not intended to limit or restrict the scope of the invention which is specified and defined by the appended claims.