Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
  • F24D11/00—Central heating systems using heat accumulated in storage masses
  • F24D11/002—Central heating systems using heat accumulated in storage masses water heating system
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D20/00—Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00
  • F28D2020/006—Heat storage systems not otherwise provided for
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D20/00—Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00
  • F28D2020/0065—Details, e.g. particular heat storage tanks, auxiliary members within tanks
  • F28D2020/0082—Multiple tanks arrangements, e.g. adjacent tanks, tank in tank

Definitions

• This invention relates generally to stored energy liquid heaters, employing thermal storage.
• Heaters of this type have proven advantageous in supplying contin ⁇ uous heat at controlled temperatures to space heating 5 and process application, from heat sources which are aperiodic in nature.
• a particular application involves the use of electrical energy during "off-peak” periods for "equalizing" utility electric generating capacity, thereby improving overall efficiency of the supplying 0 electrical utility system through load management (Ref. Fig. 5).
• the particular configuration disclosed employs water heated above its atmospheric pressure and temper ⁇ ature, allowing increased energy storage.
• a storage tank or container having essentially a vertical orientation or aspect ratio, i.e., wherein its vertical dimension is some multiple of its diameter, in conjunction with a novel orifice/standpipe flow control, provides increased utilization of the stored energy heat through improved internal storage temperature distribution.
• the invention disclosed here provides increased heater reliability through elimination of the above mentioned mixing valve, and essentially extends the capability of the heater to supply energy at a pre ⁇ determined temperature through better utilization of the storage medium.
• an object of this invention to provide a stored energy heater having extended supply capabilities through control of internal mixing and tem ⁇ perature distribution of the storage medium.
• An- additional object of this invention is to provide a standpipe/orifice combination which apportions liquid storage media so as to maintain storage outlet temper ⁇ ature by minimizing mixing with return liquid.
• a plurality of storage tanks consisting of a single master and one or more slave storage tanks is utilized to store periodically available heat, and supply contin- uous heat to a connected system, at a predetermined temperature substantially lower than that of the storage medium.
• An external dual concentric tube heat exchanger is utilized wherein the higher temperature storage or transfer liquid is circulated through an inner tube, while the system liquid or water flows through an annular space between the inner tube and a concen ⁇ trically disposed outer tube or conduit. Heat with ⁇ drawal from the above mentioned storage tanks is accom ⁇ plished through the use of a unique stand pipe-orifice combinati ' on contained in each tank.
• System demand controls the operation of a liquid pump, which on initial reduced flow operation circulates the storage fluid through a lower portion of the tank.
• Flow of high temperature storage liquid in this mode is controlled by the stand pipe orifice.
• the orifice- /standpipe combination therefore control heat extrac ⁇ tion, and storage container internal liquid flow patterns so as to essentially confine withdrawal to pre ⁇ determined portions of the storage.
• a temper ⁇ ature signal increases the pumping capacity thereby modifying the flow patterns through the standpipe and orifice combination to readjust storage fluid flow so that a major portion of the circulated storage ' fluid is
• a standpipe/orifice combination is utilized wherein total stored liquid outflow exits a tank at its lower extremity.
• Storage liquid or water is drawn from a stor ⁇ age tank through the standpipe upper end and an orifice in combination flow.
• the particular orifice utilized provides preferential withdrawal, particularly at lower withdrawal flow rates, from storage liquid located below the tank return. In this way mixing of higher temper ⁇ ature storage water and lower temperature return water is minimized providing extended storage water outflow over a broader demand range.
• the disclosed heater provides extended output a predetermined temperature, through the use of a stand pipe/orifice combination providing load-adjusting flow and temperature control of the storage medium. This discovery further allows operation of the disclosed heater without the use of a temperature sensitive mixing valve utilized in the prior art systems.
• slave tanks can be oper ⁇ ated in flow parallel, having flow and temperature
• Figure 1 is a semi-pictorial elevation/front view of a two unit (one master, one slave) with a portion of the master outer shell removed, showing essential locations of the control panel, external piping, heat exchanger, and the insulation-housing envelope.
• Figure 2 is a pictorial semi-schematic of the above mentioned master slave combination showing in pictorial/symbolic/circuit notation essential flow paths, and associated control components.
• Figure 3 is a perspective, semi cut-away view of the lower or control portion of a master unit. Particularly disclosed is termination of the concentric tube heat exchanger, system and slave unit connections, and loca- tion of a "typical" tank temperature control element.
• Figure 4 is a partial section of the master unit shown on Figure 1, particularly showing the heat exchanger location and its interconnections to the master storage container. Flow directions are schemat- ically shown.
• Figure 5 is a sectional view of the orifice/stand ⁇ pipe combination.
• Figure 6 is a sectional view of an alternate orifice- /standpoint embodiment.
• Figure 7 is an article "Electric Heat; The Right Price at the Right Time”; Technology Review, Volume 82, No. 3., Dec/Jan 1981.
• a master module 1 and slave module 2 are shown piped so as to provide essentially parallel flow of an isolated liquid storage medium, hereinafter described as storage water contained in master tank 6, and slave tank 7 through said tanks.
• Electrically immersion heating elements 60 and 61 are located adjacent to the bottom of the tanks 6 and 7, as shown.
• Standpipes 53 amd 54 are contained in each tank having am open end 50, 51 and lower orifice 41 and 42- respectively arranged to be below the upper level of tank storage water at all times.
• OMFI heat withdrawal from the parallel connection of slave and master as disclosed through opening connecting valves 69, will proceed in a manner identical to that of the master alone.
• an essen ⁇ tially circular concentric tube heat exchanger assembly 20 is disposed coaxial to the lower extremity of the tank 6.
• a pump 25 provides circulation of the storage water via exit 40 and inlet 35 of the tank.
• the concen- trie tube heat exchanger provides a flow passage or con ⁇ duit 22 internal of an outer conduit 21. This arrange ⁇ ment provides an annular flow space 23.
• the pump 25 circulates heated water drawn from the tank 6 via the standpipe 52 through both the upper end 50 and the orifice 41 as will be further dis ⁇ cussed.
• the high temperature heat source fluid in this case water, exits the tank at 40, passes through the inner heat exchange conduit 22, the pump 25 and is returned to the tank via inlet 35.
• System water enters the annular flow space 23 (ref. Figure 4) via inlet 5, and exits at the outlet 55, returning to the system via flow path 15.
• a temperature sensitive element 52 has its sensing portion immersed in the storage water at a predetermined
• OMFI location which essentially divides the storage tank into a mix portion 65, and a stratified portion 70.
• Other control elements such as a master storage heat exchanger outlet temperature control 31, a storage pres- sure relief valve 30, and a drain valve 11 provide required control and access of the heating fluid/storage in master .module 1.
• a two unit embodiment employing a master module 1 and slave module 2 is arranged to have parallel flow from the pump 25 via interconnecting conduits 32 and 10, allowing extraction of heated storage liquid contained in the slave tank 7 via the standpipe/orifice combination 51, 54 and 42 as discussed above.
• An electrical control panel assembly 75 is shown attached to the outer shell 16_. No details are provided as the panel is not a part of the invention, providing electrical energy to heating elements 60 during desig ⁇ nated "off peaks" periods through the use of conven ⁇ tional electrical contactors. Maximum heat input is controlled by tank temperature controls 52 and 52a, pro ⁇ viding power cutoff when a storage temperature of 280°F is attained. Additinal over temperature protection is provided by master and slave storage pressure relief valves 30 and 29 respectively. A pressure/temperature gage 8 is provided for monitoring tank storage condi ⁇ tions.
• system water initially entering the annular flow space 23 of the concentric tube exchanger 20 enters at ' 5, passes through the annular space 25, and exits at heat exchange outlet 55.
• system water reaches a predetermined temperature, thus reducing the temperature of the aquastat or temperature sensitive switch 56 and initiating operation of the pump 25 is initiated.
• Heated storage water is then circulated via the inner heat exchanger tube 22, hot water exit 40, and tank return 35, .supplying heated system water.
• flow through the tank 6 is predominently limited
• OMPI utilization of remaining stored heat due to its increased energy or available heat As shown on Figure 2, a slave module 2 incorporating identical elements of the master module 1 and the utilizing a pump-heat exchanger in common, results in combination having essentially doubled heat capacity. Obviously, those skilled in the art will realize that allowing for increased pumping requirements, a plurality of slave tanks could be utilized. Thus, the disclosed heater is also modular in nature, allowing economical capacity adjustment to particular load requirements.
• the particular aspect ratio of the storage tank dis ⁇ closed also provides a solution to the "flashing" phe ⁇ nomena disclosed in the earlier mentioned prior art. It has been discovered that the disclosed location of tank inlet 35, storage water orifice 41, and immersion ele ⁇ ments 61, result in initial withdrawal of the heated storage water at a temperature and flow rate, substan ⁇ tially below that of the stratified tank. Therefore, difficulties due to flashing of the external system water in the area internal of heat exchanger 20 at location 55, where heated system water exit and high temperature storage water from storage via tank exit 40 have a minimum temperature difference, is prevented. Continued flow through orifice 41 results in moderating storage water temperature through mixing in the low zone 65, further eliminating flashing of the heated system.. water, which would most likely occur at exit 55 of the heat exchanger 20 as described above. It should be noted that prior art systems require the use of a substantially unreliable, and relatively expensive mixing valve to eliminate flashing when stor ⁇ age tank orientation was essentially horizontal.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Heat-Pump Type And Storage Water Heaters (AREA)
• Domestic Hot-Water Supply Systems And Details Of Heating Systems (AREA)
• Other Air-Conditioning Systems (AREA)

Applications Claiming Priority (2)

Publications (2)

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Family Applications (1)

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• 1982
  • 1982-06-01 EP EP19820902229 patent/EP0081567A4/fr not_active Withdrawn
  • 1982-06-01 WO PCT/US1982/000756 patent/WO1982004370A1/fr not_active Application Discontinuation
  • 1982-06-02 GR GR68328A patent/GR79493B/el unknown
  • 1982-06-04 CA CA000404511A patent/CA1187750A/fr not_active Expired

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