Abstract:
A system dehumidifies a non-environmentally controlled, enclosed space of a building, for example a crawlspace, using a dehumidifier unit comprising an evaporator coil, a condenser coil, and a compressor arranged for circulating heat exchanger fluid through the coils. A fan operates in series with closed loop ducting to communicate air from the space to the dehumidifier unit and back to the space independently of an HVAC system of the building. The fan and dehumidifier unit are responsive to a dehumidistat. A distributed outlet distributes air from the unit to peripheral positions about the space. A heater is coupled in series with the ducting for heating air circulated therethrough.

Description:
[0001]    This application claims the benefit under 35 U.S.C.119(e) of U.S. provisional application Ser. No. 60/808,978, filed May 30, 2006. 
     
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to a system for dehumidifying and more particularly relates to a system for dehumidifying enclosed spaces, for example crawlspaces or attics in buildings and the like. 
       BACKGROUND 
       [0003]    In various enclosed spaces, in building and the like excessive moisture build-up or humidity in the air can cause undesirable growths of mold, bacteria or various undesirable microbes. Accordingly it is desirable to remove moisture from such enclosed building spaces. 
         [0004]    Small stand alone units are known for dehumidifying in which a dehumidistat, a fan for circulating air and coils of a condenser and evaporator cycle are provided on a common housing, however, such units typically have a limited capacity to remove moisture, are ineffective at circulating air through a large space, and have no on-going monitoring ability. 
         [0005]    U.S. Pat. No. 6,826,920 belonging to Wacker and US Application Publication No. 2006/0086112 belonging to Bloemer et al each disclose systems for controlling humidity, however neither includes its own fan, but rather requires operation in conjunction with the air handler of an HVAC environmental control system of the building. 
         [0006]    US Application Publication No. 2005/0005616 belonging to Bates et al discloses a fungus abatement system for a lower enclosed space in a building. The system is an open loop system which draws air from the space at plural locations and exhausts the air externally from the building. Such a system is not well suited for use in colder environments due to the resulting heat loss of repeatedly exhausting air which is heated in the space by convection or conduction. Furthermore, the system is not effective for dehumidification in environments where the air drawn back into the space is also humid. 
       SUMMARY OF THE INVENTION 
       [0007]    According to one aspect of the invention there is provided a dehumidifying system for dehumidifying a space of a building, the system comprising: 
         [0008]    a dehumidifier unit comprising an evaporator coil, a condenser coil, and a compressor arranged for circulating heat exchanger fluid through the coils; 
         [0009]    ducting arranged for communicating from the space to an inlet of the dehumidifier unit and for communicating from an outlet of the dehumidifier unit to the space; 
         [0010]    a fan arranged for circulating air through the ducting between the space and the dehumidifier unit; 
         [0011]    a dehumidistat arranged for communication with airflow from the space to the dehumidifier unit to measure a humidity level of air in the space, the dehumidistat having a set point humidity level and being arranged for activating the dehumidifier unit responsive to the humidity level in the space exceeding the set point humidity level. 
         [0012]    By providing a system in which ducting communicates a dehumidifier unit to a space to be dehumidified, a fan can circulate the air thoroughly throughout the space in a closed loop configuration with the space so that all humid air can be brought into contact with the dehumidifier unit for dehumidification. Supporting the dehumidistat in communication with the air being circulated ensures that the system operates in the most efficient manner. 
         [0013]    When the system is provided in combination with a building including a controlled space in communication with an air handler of an environmental control system of the controlled space and an uncontrolled space, the ducting is preferably arranged in communication with the uncontrolled space independently of the air handler. The dehumidifying system is thus well suited as an add-on to a building already having an HVAC system in which the dehumidifying system communicates with a crawlspace or basement area independently of the HVAC system. 
         [0014]    The dehumidifier unit may be supported in the controlled space of the building and arranged to communicate with the uncontrolled space of the building. 
         [0015]    There may be provided a single common intake arranged to be supported centrally in the space, the ducting communicating between the common intake and the inlet of the dehumidifier unit. 
         [0016]    Furthermore, there may be provided a distributed outlet arranged to be supported in the space for communication with the space at a plurality of positions spaced generally about a periphery of the space, the ducting communicating between the outlet of the dehumidifier and the distributed outlet. The distributed outlet acts as a manifold to ensure that dried air, from which the dehumidifier has removed moisture, is thoroughly spread through the space to be dehumidified. Accordingly a greater amount of moisture remaining in the space can be collected by the drier air and drawn towards the common intake which is preferably centrally located in relation to the peripherally distributed outlet. 
         [0017]    The inlet and the outlet of the dehumidifier are preferably arranged to communicate with the space in a closed loop configuration. 
         [0018]    Both the fan and the compressor may be operated simultaneously responsive to the dehumidistat and a timer. 
         [0019]    The fan may also be responsive to a timer to circulate air periodically through the space independently of the operation of the dehumidifier unit to ensure accurate moisture determination by the dehumidistat. 
         [0020]    In some instances, both the fan and the compressor may be responsive to a timer to periodically circulate and dehumidify air within the space. 
         [0021]    There may also be provided a heater for heating the space, which is preferably coupled in series with the ducting for heating air circulated therethrough. 
         [0022]    The heater may be in communication between the space and the inlet of the dehumidifier unit in some instances. Pre-heating the air entering the de-humidifier unit increases the resistance to ice formation on the evaporator coils to ensure continued efficient operation of the de-humidifier unit. 
         [0023]    In other instances the heater may be in communication between the outlet of the dehumidifier unit and the space. In this instance, the heated air is arranged to collect a larger amount of moisture from the space prior to re-entering the dehumidifier unit where the moisture is collected. 
         [0024]    The heater may be responsive to a thermostat supported within the space or responsive to a flow of air through the ducting. 
         [0025]    There may be provided a de-icing mechanism coupled to the evaporator coil and arranged for selectively heating the evaporator coil such that ice is arranged to be removed from the evaporator coil. 
         [0026]    The space may be provided in combination with an enclosed and unheated space within a building, comprising for example a crawlspace of the building. 
         [0027]    When the building includes a plumbing drain, the dehumidifier unit may include a drain arranged to drain condensate from the evaporator coil directly to the existing plumbing drain of the building. 
         [0028]    One embodiment of the invention will now be described in conjunction with the accompanying drawings in which: 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0029]      FIG. 1  is a schematic view of the system installed for communication with the crawl space of a building. 
           [0030]      FIG. 2  is an enlarged schematic view of the ducting communicating between the dehumidifier unit and the space to be dehumidified. 
       
    
    
       [0031]    In the drawings like characters of reference indicate corresponding parts in the different figures. 
       DETAILED DESCRIPTION 
       [0032]    Referring to the accompanying figures there is illustrated a dehumidifier system generally indicated by reference character D. The dehumidifier system D is particularly suited for communication with an enclosed space, which may be heated or unheated, for example a crawl space  8  below a building  16 . 
         [0033]    In a typical installation, the system D is installed independently of an HVAC system of a building including a controlled space in communication with an air handler of HVAC environmental control system. The system D is particularly suited to being in communication with an uncontrolled space of the building which does not communicate with the HVAC system. 
         [0034]    The system includes a dehumidifier unit supported within a suitable housing  14  or container within which various operating components for dehumidification are supported. The housing  14  of the dehumidifier unit is supported in the controlled space of the building and is arranged to communicate with the uncontrolled space of the building through suitable ducting in communication with the uncontrolled space independently of the air handler. Both of the uncontrolled and controlled spaces typically comprise an enclosed space. 
         [0035]    Within the housing there is provided a de-icing coil  1  which serves to melt any ice built up on an evaporator  2  also supporting within the housing. The evaporator  2  serves to condense moisture in the air which passes thereacross by absorbing heat from the moisture in the air which causes heat exchanger fluid within coils of the evaporator to be evaporated. 
         [0036]    Coils of the evaporator  2  communicate in series with a condenser  3  which serves to condense the heat exchanger fluid therein in a second phase of the heat exchanger cycle. Also within the housing is a compressor  4  which serves to compress the heat exchanger gas for circulating the heat exchanger fluid through the evaporator and condenser. The operation of the dehumidifier unit alone operates generally according to traditional and conventional refrigeration techniques. 
         [0037]    The housing also includes a fan  5  which serves to circulate air through the housing of the dehumidifier unit by both drawing air from the space and returning dehumidified air back to the space. 
         [0038]    The ducting includes a supply air duct  6  which communicates from an outlet of the dehumidifier unit to a series of air distribution ducts  15  to supply dehumidified air from the unit at the fan outlet back into the space of air to be dehumidified. The ducts  15  comprise distributed manifold outlet arranged to be supported in the space for communication with the space at a plurality of positions spaced from one another generally about a periphery of the space. The dried air from the dehumidifier is thus directed into all areas of the space to collect moisture evenly from the space. 
         [0039]    The ducting further includes a return air duct  7  which includes an inlet located within the space which draws humid air from the space and communicates this humid air to the inlet of the dehumidifier unit. An air filter  12  is mounted in the space, in series with the airflow from the space to the unit, at the inlet end of the return air duct which returns air from the space to the dehumidifier unit. The inlet within the space comprises a single common intake arranged to be supported in the space at a central location to be generally evenly spaced from the spaced positions of the distributed outlet  15 . This further ensures that moisture is evenly collected from the space. 
         [0040]    A heater  9 A is mounted in series with the supply air duct  6  so that the dehumidified air can be heated prior to being returned into the space to be dehumidified. The heater comprises an electrical resistance heater which is activated responsive only to a flow of air through the supply air duct. The heater  9 A is controlled by a thermostat  11  which is supported within the enclosed space  8  to be dehumidified for operating the heater only when temperature in the space falls below a prescribed set point of the thermostat  11 . 
         [0041]    Optionally, a heater  9 B is mounted in series with the return air duct  7  which directs air to the inlet of the dehumidifier unit. The heater  9 B is located within the controlled space  1   6 A, separate from, but close to the inlet of the dehumidifier unit. The heater  9 B in the duct  7  leading to the dehumidifier unit serves to prevent freezing up of condensate on the coils of the evaporator  2 . The heaters  9 A and  9 B can be used in the same embodiment or independently of one another in different embodiments of the invention. 
         [0042]    Operation of the dehumidifier unit is responsive to both a timer  10  supported on the unit and a dehumidistat  13  which measures a level of humidity in the surrounding air. The dehumidistat  13  is supported in communication with airflow from the space to the unit, for example centrally within the space  8 , where air is circulated to optimize the reading of the humidity level. The dehumidistat  13  has a set point humidity level which can be set at an adjustable level as the user or installer desires. Whenever the level of humidity exceeds the set point humidity level, the dehumidistat signals the dehumidifier unit to operate both the compressor and the fan together for both circulating air and dehumidifying the air being circulated in a single operation. 
         [0043]    The dehumidistat  13  may comprise two separate controls designated as a winter controller and a summer controller or a single dual function controller. In each instance, the dehumidistat  13  is operable in a winter mode in which the dehumidistat is operable relative to a winter set point and a summer mode in which the dehumidistat is operable relative to a summer set point. The winter and summer set points comprise different moisture level set points which represent different recommended moisture levels depending upon different seasons. 
         [0044]    The timer  10  is set to also operate the compressor and fan together at periodic intervals, for instance once or twice a day, to maintain proper circulation of air through the enclosed space  8 . Once the timer begins operation for a prescribed period of time, if the circulated air is detected by the dehumidistat to be too humid, continued operation of the dehumidifier unit results. Alternatively if after some initial period of operation responsive to the timer, the dehumidistat detects that the humidity level is below the set point humidity level, continued operation of the dehumidifier unit can be ceased which will in turn cease operation of the heater as a result of the discontinued airflow through the ducting. 
         [0045]    As described herein, when the system operates and is turned on, the system provides air circulation through the area where it is intended. As the air and moisture pass through the air handler, the moisture is captured at the evaporator and sent out by a direct connection to a corresponding drain of the building. When the moisture level reaches a dehumidistat set point, the entire system shuts down. Periodically the system will turn itself on by way of a programmable timer to sample the moisture content in the air, and depending on the moisture level in relation to the dehumidistat set point, the system either continues running or shuts off. In addition to the timer, the dehumidistat also activates the system when the humidity in the space area exceeds the set point of the dehumidistat. The system is particularly suited for use in crawl spaces of houses and building or any other confined spaces where moisture level needs to be monitored and controlled. The system will be available through a range of sizes from very small units to very large units to accommodate a corresponding range of enclosed spaces which may also vary in size. 
         [0046]    Since various modifications can be made in my invention as herein above described, and many apparently widely different embodiments of same made within the spirit and scope of the claims without department from such spirit and scope, it is intended that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense.