Method, System, and Apparatus for Modular Central Plant
There is provided a system and method for a modular central plant. In one implementation, the inventive system includes a chiller unit and cooling tower that are designed to be modularly assembled, transported, and interconnected, thereby decreasing system cost and assembly time, increasing system maintainability, and improving scalability for increasing capacity at a future date. The removable wall panels and roof of an embodiment of the present invention aid in maintainability by providing enhanced access to critical system components such as the chiller assembly. The modular architecture of the present invention allows for speedy delivery and installation, and with only external electrical and water connections needed, the system can become rapidly operational.
This application claims the full benefit and priority of U.S. Provisional Application Ser. No. 60/805,213, filed on Jun. 19, 2006, the disclosure of which is fully incorporated by reference herein for all purposes.
TECHNICAL FIELDThe present invention relates generally to the cooling and heating equipment industry, and more specifically to methods, systems, and apparatus for modular central plants for providing heated and chilled water for building climate control.
BACKGROUNDTo provide for efficient building climate control, particularly in larger buildings, chilled or heated water is typically furnished to building air handling systems from a central plant. These central plants typically incorporate one or more chiller/boiler units and cooling towers, and comprise sophisticated combinations of electrical and mechanical control systems, mechanical piping and fluid processing, pumps, fans, shelters, and engineered structural elements. Also, in almost all cases, central plants are designed from scratch for each building application, and although many commercially available components are utilized, installation requires substantial mechanical construction, field assembly, and system integration effort at the building site. As a result, the cost to design, deliver, and install a central plant is a major factor in the overall expense of building construction, and often impacts the schedule for building construction completion.
As a further shortcoming of prior art custom-designed central plants, nonstandard components and layouts are often utilized to best fit unique installation requirements. In the long run, however, selection of nonstandard components only serves to further drive up cost and delays building completion schedules. Further, the schedule and cost constraints commonly imposed on central plant installation often results in the omission of features that reduce overall system maintenance and operational costs. As a result, building owners using prior art central plant designs are faced with suboptimal long-term operational expenses.
As a further limitation of prior art central plants, capacity expansion to accommodate increased chilled or heated water demand requires expensive redesign and retrofit. Future capacity is generally not considered in designing and installing prior art central plants, and the case-by-case reengineering of each plant for additional load is a major detriment to building owners.
It would be an advance in the art to address the aforementioned problems in the prior art and to provide for a method, system, and apparatus for a central plant that is more cost effective to design, requires less time and expense to install, accommodates expansion, and provides superior maintenance for long term cost-effective operation.
SUMMARY OF THE INVENTIONIt is an object of the present invention to improve various problems associated with the prior art. In one implementation, the inventive system includes a chiller unit and cooling tower that are designed to be modularly assembled, transported, and interconnected, thereby decreasing system cost and assembly time, increasing system maintainability, and improving scalability for increasing capacity at a future date. The removable wall panels and roof of the present invention aid in maintainability by providing enhanced access to critical system components such as the chiller assembly. The modular nature of the present invention allows for speedy delivery and installation, and with only electrical and water connections the system can become rapidly operational. The structural design of the inventive system allows for installation on either a grade or on support posts for roof installation, thereby substantially reducing the structural preparation work that is necessary to install a central plant system on site. Further, by interconnecting multiple modular components of the present invention, central plant capacity can be quickly scaled up without substantial engineering to provide optimal central plant support for buildings of any size.
Additional embodiments include a modular central plant system comprising: a plurality of prefabricated chiller modules having substantially similar exterior dimensions, each of said plurality of chiller modules including a human-accessible environmental shelter respectively enclosing at least part of each of the plurality of chiller modules; and a means for sealably joining said plurality of environmental shelters to define a unified enclosed interior volume wherein: each of said plurality of prefabricated chiller modules includes a plurality of fluid-bearing pipes so disposed as to allow substantially direct inter-module interconnection between respective fluid bearing pipes from each of said plurality of chiller modules when respective exterior mating surfaces of each of said plurality of chiller modules are approximated and brought within substantial aligned proximity of each other.
Still referring to the previous embodiment, the modular central plant system further comprises a plurality of cooling towers, each of said plurality of cooling towers is respectively interconnected to each of said plurality of prefabricated chiller modules, wherein each of said plurality of cooling towers is respectively substantially aligned with each of said plurality of prefabricated chiller modules.
As described herein, the capacity that is desired to accommodate particular building requirements by be achieved by scalably adding modular chiller-water tower components until the prescribed ratings are reached. Embodiments address the method of interconnecting modular components. One exemplary method for constructing a modular central plant comprises: providing a plurality of prefabricated chiller modules wherein each of said plurality of prefabricated chiller modules has at least one open side defining access to an interior space therein; aligning in substantial parallel respective central axes of said plurality of prefabricated chiller modules, wherein at least one open side of each of said plurality of prefabricated chiller modules is made substantially adjacent to at least one open side of another prefabricated chiller module of the plurality of prefabricated chiller modules; approximating a plurality of respective mechanical interfaces of said plurality of prefabricated chiller modules and thereafter respectively interconnecting said plurality of mechanical interfaces; and interconnecting piping headers between each of the fastened plurality of prefabricated chiller modules.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and together with the description, serve to explain the principles of the invention.
Referring to
The modular chiller-tower units, once assembled at the jobsite and connected to building services, are fully self-contained and capable of independent operation. In one embodiment of the present invention, no additional controls or building automation systems are needed to bring the modular units into operational status. While prior art systems required substantial on-site preparation activity to assemble and integrate chiller units and cooling towers, in the present invention, the cooling tower assembly includes all required support steel, controls, electrical and piping.
The modular chiller units are designed to be easily mechanically interconnected in a manner as shown in figures such as
Piping layouts in both the chiller modules and cooling towers are designed to allow integrated chiller-cooling tower modules to be “stacked” side by side in series, whereby cooling capacity is increased as additional modules are interconnected to the modular central plant system. For example, chilled water return and supply lines that ultimately connect to the building being serviced by the modular central unit plant system (shown as, for instance, CHWR and CHWS pipes, respectively, on
With this internal piping arrangement, a standard modular central plant design can accommodate a wide range of capacities. For example, by proper choice of components, a single compact modular package can be easily scaled from 100 ton to 600 ton capacity. By interconnecting additional modules, capacity can be scaled up to the thousands of tons of capacity. As shown in
The modules of the present modular central plant system are designed to be easily truck mounted and transported so as to minimize on-site assembly efforts. As an exemplary embodiment, in one configuration, one chilling module is loaded per truck inclusive of all items needed for a completely operational system with the exception of the cooling towers, which may be sent directly from the cooling tower manufacturer to the job site. The design of the present invention allows for components to be strategically placed and nested on a trailer and/or ship as required for delivery to the end user.
As shown in
Embodiments of the present invention include complete chemical treatment controls and distribution system for both the condenser water “open loop” and the chilled water “closed loop” systems. The chemical treatment system is easily expandable to accommodate expansions arising from the present modular design. The chemical treatment system is designed to sufficiently monitor and distribute chemicals to the individual modules as required to assure the water quality of both the “open and closed loops” to predetermined standards.
One embodiment comprises an all inclusive Chemical Treatment Skid that includes all necessary equipment as required to maintain a prescribed water quality. This includes, for example, the main water treatment controller, water sampling coupons, flow meter/water sampling meter, closed loop pot feeder, motorized bleed valve, chemical storage tanks and chemical metering pumps. This Skid contains with all its components monitor and control the water quality of the condenser water (CW) system “open loop”. The programmable water treatment controller uses a remote water quality sensor to monitor the CW loop. When the water quality drops below the prescribed parameters, the controller energizes the chemical pumps and injects biocides and inhibitor chemicals as required to maintain a certain level of quality. The controller also monitors the amount of total dissolved solids in the water (TDS) when the TDS is above the prescribed parameters the controller opens a motorized dump valve. This valve allows dirty water to drain/bleed from the system until enough make up water (fresh water) has mixed with the CW loop water to bring the TDS down top acceptable limits. Once these limits have been reached the motorized valve closes allowing the cycle to reset and begin again.
This skid also on contains a pot feeder that is tied to the chilled water (CHW) system “closed loop”. This pot feeder is used as a means to manually feed chemicals into the CHW system as required to inhibit rust and the growth of biologicals.
One aspect of embodiments of the present invention is the use of a modular header system that allows for easy and simple expansion to the base water treatment system as additional modules are added. Each module then independently inter-connects this chemical treatment header to their individual CW distribution piping “open loop.” This connection incorporates two special devices, the first, is a one way check valve on the CW supply line that allows water to flow only from the module into the chemical treatment header, not from the header to the module. The second is a motorized valve that is interlocked with the module's CW pump. When the pump is on the valve is open and when that pump is off the valve is closed. This configuration isolates the CW return pipe from the chemical treatment header similar to the check valve at the supply line, allowing the water to flow back into the individual modules CW system when only when it is in operation.
The combination of using these two valves and the header system allow only water from the modules in operation to supply water to the Chemical Treatment Skid. This way, only the equipment that is operating can get its water monitored, can get its required chemicals and is allowed to bleed/replenish water. In certain embodiments, systems that are offline stay isolated from the Chemical Treatment System entirely.
With this modular approach, whether only one module is running or if any combination of modules are running, the disclosed header and inter-connect system along with the described Chemical Treatment Skid maintain the prescribed water quality standard at least equivalently to those systems that utilize alternative prior approaches to water treatment.
Prior art central plants often are difficult to maintain because of impaired access to key components of the system such as chillers or pumps. While these prior art systems provide some protection from the elements through custom enclosures, they do so at the expense of maintainability. The present invention addresses these limitations, in part, by providing customer-removable side panels and roof elements while making such panels and roof elements, when installed, resistant to wind, precipitation, and dust. In one embodiment, neoprene gaskets are utilized at mechanical interfaces to provide environmental seals. The roof of a modular unit assembly is completely and easily removable (such as by crane or winch) for complete access to internal components and equipment. Further, individual wall panels are removable as needed for select accessibility. In one embodiment of the present invention, the layout and design of the internal modular elements provides maintenance access to all internal components once panels are removed, even when modules are interconnected in parallel or in series (see, e.g.,
In one embodiment main access into the modular unit of the present invention is provided through a large overhead door located at one end of the module. This door allows for equipment and personnel to easily enter and exit module to perform routine maintenance on internal equipment. As shown in a block diagram in
Chiller modules of the present invention are designed as an unoccupied enclosure to house the components necessary to produce chilled or heating hot water. Access to this enclosure is generally to be used for the maintenance and replacement, and therefore embodiments include controls and safeguards to protect the personnel who enter chiller modules equipment for maintenance.
In some embodiments, the enclosure is equipped with specific access controls and interlocks. Ventilation fans and lighting to turn on when maintenance personnel energize entry door with key operated switch by rotating it to the open (occupied mode). In various embodiments, when the door is in the closed position (unoccupied mode) all lighting, ventilation and convenience power shut off. The door can only be closed and/or opened from the outside of the equipment enclosure.
In certain example embodiments, via exemplary design and sizes of the present chiller module enclosures enclosure, the afore mentioned equipment door opening size and location of the equipment module (for example, 20 feet from building egress opening) are as such that they fall under the ASHRAE 15-1994 “Natural Ventilation” clause which does not require any mechanical ventilation, yet enhanced safety embodiments of the invention provide for a fan that is sized at the ASHRAE prescribed “Alarm Ventilation Rate.” The exemplary 20 feet from egress opening of building also falls outside of the International Building Code Section 1103.2 occupancy classification.
Embodiments include controls for system function as well as chemical treatment monitoring and controls. The system can be interfaced with and controlled from a single point located outside the enclosure via a handheld interface device or by a wired or wireless interface with a building automation system. Optionally, embodiments of enclosed spaces of the present design include air conditioners to ensure the proper operation of the internal components (for example, between 95 degrees cooling and 40 degrees heating).
Turning to
Additional embodiments of cooling tower aspects of the present invention may be found in
The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.
Claims
1. A modular central plant system comprising:
- a plurality of prefabricated chiller modules having substantially similar exterior dimensions, each of said plurality of chiller modules including a human-accessible environmental shelter respectively enclosing at least part of each of the plurality of chiller modules; and
- means for sealably joining said plurality of environmental shelters to define a unified enclosed interior volume wherein: each of said plurality of prefabricated chiller modules includes a plurality of fluid-bearing pipes so disposed as to allow substantially direct inter-module interconnection between respective fluid bearing pipes from each of said plurality of chiller modules when respective exterior mating surfaces of each of said plurality of chiller modules are approximated and brought within substantial aligned proximity of each other.
2. The modular central plant system as defined in claim 1, further comprising means for electrically interconnecting each of said of prefabricated chiller modules.
3. The modular central plant system as defined in claim 2, wherein the electrical connection means further comprises pin and sleeve connectors.
4. The modular central plant system as defined in claim 1, further comprising a relocatable water treatment skid.
5. The modular central plant system as defined in claim 1, wherein each of said plurality of prefabricated chiller modules further comprises a supporting frame including a hook-and-roller interconnection interface.
6. The modular central plant system as defined in claim 1, wherein each of said plurality of prefabricated chiller modules further includes a fastenably removable and replaceable roof.
7. The modular central plant system as defined in claim 1, wherein each of said plurality of prefabricated chiller modules further includes fastenably removable and replaceable wall panels.
8. The modular central plant system as defined in claim 1, wherein each of said plurality of prefabricated chiller modules further comprises an personnel access interlock, whereupon actuating the personnel access interlock to an open position thereof:
- an electrically operated door is translated from a closed position to an open position thereof;
- an electrically operated air exchange fan is energized; and
- at least one light fixture is energized.
9. The modular central plant system as defined in claim 1 further comprising a plurality of cooling towers, each of said plurality of cooling towers respectively interconnected to each of said plurality of prefabricated chiller modules, wherein each of said plurality of cooling towers is respectively substantially aligned with each of said plurality of prefabricated chiller modules.
10. A method for constructing a modular central plant comprising:
- providing a plurality of prefabricated chiller modules wherein each of said plurality of prefabricated chiller modules has at least one open side defining access to an interior space therein;
- aligning in substantial parallel respective central axes of said plurality of prefabricated chiller modules, wherein at least one open side of each of said plurality of prefabricated chiller modules is made substantially adjacent to at least one open side of another prefabricated chiller module of the plurality of prefabricated chiller modules;
- approximating a plurality of respective mechanical interfaces of said plurality of prefabricated chiller modules and thereafter respectively interconnecting said plurality of mechanical interfaces; and
- interconnecting piping headers between each of the fastened plurality of prefabricated chiller modules.
11. The method for constructing a modular central plant as disclosed in claim 10, further comprising electrically interconnecting the plurality of prefabricated chiller modules using pin and sleeve connectors.
12. The method for constructing a modular central plant as disclosed in claim 10, further comprising fastenably connecting vertical structural members of adjacent prefabricated chiller modules of the plurality of prefabricated chiller modules.
Type: Application
Filed: Jun 19, 2007
Publication Date: Jun 5, 2008
Inventors: Michael E. Stanfield (Gilbert, AZ), Kenneth M. Liles (Chandler, AZ), Stephen C. Mullins (Phoenix, AZ), Gary G. Niver (Maricopa, AZ)
Application Number: 11/765,423
International Classification: F28C 1/00 (20060101); F25B 7/00 (20060101);