GB2428470A - A re-heat air conditioning system - Google Patents

A re-heat air conditioning system Download PDF

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Publication number
GB2428470A
GB2428470A GB0522927A GB0522927A GB2428470A GB 2428470 A GB2428470 A GB 2428470A GB 0522927 A GB0522927 A GB 0522927A GB 0522927 A GB0522927 A GB 0522927A GB 2428470 A GB2428470 A GB 2428470A
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United Kingdom
Prior art keywords
heat
coil
run
around
cooling coil
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Application number
GB0522927A
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GB0522927D0 (en
Inventor
Peter John Bayram
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Individual
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Individual
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Publication date
Priority claimed from GB0515044A external-priority patent/GB0515044D0/en
Priority claimed from GB0515366A external-priority patent/GB0515366D0/en
Priority claimed from GB0516047A external-priority patent/GB0516047D0/en
Priority claimed from GB0516847A external-priority patent/GB0516847D0/en
Priority claimed from GB0518824A external-priority patent/GB0518824D0/en
Priority claimed from GB0520537A external-priority patent/GB0520537D0/en
Priority claimed from GB0521773A external-priority patent/GB0521773D0/en
Application filed by Individual filed Critical Individual
Publication of GB0522927D0 publication Critical patent/GB0522927D0/en
Publication of GB2428470A publication Critical patent/GB2428470A/en
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F3/00—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems
    • F24F3/06—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the arrangements for the supply of heat-exchange fluid for the subsequent treatment of primary air in the room units
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F3/00—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems
    • F24F3/044—Systems in which all treatment is given in the central station, i.e. all-air systems
    • F24F3/048—Systems in which all treatment is given in the central station, i.e. all-air systems with temperature control at constant rate of air-flow
    • F24F3/052—Multiple duct systems, e.g. systems in which hot and cold air are supplied by separate circuits from the central station to mixing chambers in the spaces to be conditioned
    • F24F3/0522—Multiple duct systems, e.g. systems in which hot and cold air are supplied by separate circuits from the central station to mixing chambers in the spaces to be conditioned in which warm or cold air from the central station is delivered via individual pipes to mixing chambers in the space to be treated, the cold air/warm air ratio being controlled by a thermostat in the space concerned, i.e. so-called Dual-duct System
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/62—Control or safety arrangements characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values
    • F24F11/63—Electronic processing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/30—Control or safety arrangements for purposes related to the operation of the system, e.g. for safety or monitoring
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/30—Control or safety arrangements for purposes related to the operation of the system, e.g. for safety or monitoring
    • F24F11/46—Improving electric energy efficiency or saving
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/70—Control systems characterised by their outputs; Constructional details thereof
    • F24F11/80—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air
    • F24F11/83—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling the supply of heat-exchange fluids to heat-exchangers
    • F24F11/84—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling the supply of heat-exchange fluids to heat-exchangers using valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F3/00—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems
    • F24F3/044—Systems in which all treatment is given in the central station, i.e. all-air systems
    • F24F3/048—Systems in which all treatment is given in the central station, i.e. all-air systems with temperature control at constant rate of air-flow
    • F24F3/052—Multiple duct systems, e.g. systems in which hot and cold air are supplied by separate circuits from the central station to mixing chambers in the spaces to be conditioned
    • F24F3/0527—Multiple duct systems, e.g. systems in which hot and cold air are supplied by separate circuits from the central station to mixing chambers in the spaces to be conditioned in which treated air having differing temperatures is conducted through independent conduits from the central station to various spaces to be treated, i.e. so-called "multi-Zone" systems
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F3/00—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems
    • F24F3/06—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the arrangements for the supply of heat-exchange fluid for the subsequent treatment of primary air in the room units
    • F24F3/065—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the arrangements for the supply of heat-exchange fluid for the subsequent treatment of primary air in the room units with a plurality of evaporators or condensers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F3/00—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems
    • F24F3/12—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling
    • F24F3/14—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by humidification; by dehumidification
    • F24F3/1405—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by humidification; by dehumidification in which the humidity of the air is exclusively affected by contact with the evaporator of a closed-circuit cooling system or heat pump circuit
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F3/00—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems
    • F24F3/12—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling
    • F24F3/14—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by humidification; by dehumidification
    • F24F3/147—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by humidification; by dehumidification with both heat and humidity transfer between supplied and exhausted air
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F3/00—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems
    • F24F3/12—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling
    • F24F3/14—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by humidification; by dehumidification
    • F24F3/153—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by humidification; by dehumidification with subsequent heating, i.e. with the air, given the required humidity in the central station, passing a heating element to achieve the required temperature
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F2221/00—Details or features not otherwise provided for
    • F24F2221/54—Heating and cooling, simultaneously or alternatively
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B13/00—Compression machines, plants or systems, with reversible cycle

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Fuzzy Systems (AREA)
  • Mathematical Physics (AREA)
  • Thermal Sciences (AREA)
  • Central Air Conditioning (AREA)

Abstract

A re-heat air conditioning system comprises conditioning of fresh and return air by using a main cooling coil 2, a run-around pre-cooling coil 1 exchanging energy with multiple run-around re-heat coils 3 located upstream of a battery of further re-heat coils 12. Pre-cooling coil 1 and re-heat coils 3 are on the same fluid circuit connected by pipework 6, 8. In a summer cycle (fig 1) no fluid flows through the further re-heat coils 12, whereas in a winter cycle (fig 1A) fluid flows through the re-heat coils 12 to further heat the air. Pre-cooling coil 1 may be located to only cool the return air (figs 2, 2A) or located to only cool the fresh air (figs 3, 3A). The system may comprise of an additional pre-cooling coil for the fresh air (1a, figs 4 - 5B) for lower percentages of fresh air, and a dehumidifying cooling coil for the fresh air (2a, figs 6 - 6B) reducing the amount of re-heat required during a dehumidification cycle. Exhaust air may adiabatically spray cooled using an exhaust air coil (1b, figs 7 - 7A) in fluid communication with the additional pre-cooling coil (1a). Pre-cooling coil 1 and the main cooling coil 2 may be combined into one single coil in series fluid communication and also in fluid communication with water chillers (14, figs 8 - 8B). Re-heat coils 3, 12 may be combined into a single coil. Main cooling coil 2 may operate on a reverse cycle for both heating and cooling (figs 10, 10A). The system may be used for controlling air temperature and humidity in multi zone (fig 11) or dual duct (fig 12) systems.

Description

ENERGY SAVING SYSTEM FOR MULTI-ZONE RE-HEAT AIR CONDITIONING
This invention relates to terminal re-heat, single-fan dual-duct and multizone air conditioning systems, and hybrid versions there- of. In particular it relates to the provision of an efficient form of re- heating far such systems., Terminal re-heat air conditioning systems are generally considered to be the simplest form of zone temperature control system; how- ever, they are very energy inefficient. This is because whichever of the zone temperature control systems has the highest demand for cooling at any time dictates the off' coil temperature from the cooling coil, with the consequence that the terminal re-heater bat- teries of most, if not all, of the other zones will require to be operated to prevent overcoaling occurring in these zones. Also, the total refrigeration cooling capacity required is derived from a summation of each zone's maximum possible peak heat gain (including occasional gains from equipment, etc.), rather than being derived from the peak envelope' heat gain plus an estimated diversified fraction of all occasional gains; this generally results in a sign- ificantly higher refrigeration cooling capacity being required than for other types of air conditioning systems.
According to the present invention there is provided a run-around precooling coil, located upstream of the main cooling coil of a terminal re-heat system, that exchanges energy with multiple ter- minal run-around re-heat coils, each located immediately upstream of conventional' terminal re-heater batteries. Pt Summer ambient conditions the coil run-around system provides free' re-heat to offset the overly cold duct supply air temperature to some of the zones. In turn, the overly cold air flowing through these run- around re-heater coils provides for pre-cooling that is equal to the total output of the re-heaters, and thus the required total re- frigeration cooling capacity is reduced and can be conventionally calculated. It can also be seen that such a run-around system re- duces both the cooling and heating energy consumption of a terminal re- heat system. Another energy saving effect is that the cooling system now responds to changes in zone heat gain, such that if lights, or equipment are switched off there would be an equal in- crease in free' run-around re-heat and a correspondingly equal in- crease in free' pre-cooling. With a conventional terminal re-heat system any reduction in a zone's heat gain (other than the zone with peak gains) not only results in a correspondingly equal in- crease in re-heat output, but also no reduction in refrigeration cooling.
A variation would be to reverse-cycle changeover the main cooling coil to a heating mode. At intermediate season conditions such changeover would be pulsed, as may be computer software controlled, and the action of the motorised control valves of the run-around re-heat/re-cool coils reversed. With this system a conventional' terminal re-heating system is eliminated, thus reducing costs.
P terminal re-heat system, with run-around pre-cool/re-heat, offers a simply applied and economical means of providing for multi-zone control to smaller packaged' air conditioning equipment systems, including those for residential' systems.
Run-around pre-cool/re-heat systems can also be applied to dual- duct and multizone air conditioning systems. In the case of a dual- duct system having a single common main cooling coil there would be a run-around pre-cooling coil with a corresponding run-around re- heat coil (and a conventional' re-heater) in the hot deck, or hot duct. In the case of a multizone system, the main cooling coil would require to be extended into the hot deck and the run-around pre-cooling coil be the size of the cold deck; with the run-around re-heat coil in the hot deck. Economy of operation is achieved in Summer in the case of a single fan dual-duct system by the free' re-heat provided by the run-around re- heating coil in the hot duct.
In the case of a multizone system the hot deck air is now dehumidi- fied, and the cold deck supply air temperature need not be as low as might normally be required and the pre-cooling coil further rai- ses the minimum required main cooling coil temperature, which would increase the refrigeration system COP (coefficient-of-performance).
With a run-around system a single-fan dual-duct system would be as similarly effective as a more complex two-fan system. In both cases the run-around system affords similar benefits to those ascribed to terminal re-heat systems.
When the main cooling coil temperature control may be overridden to increase dehumidification cooling, there would be an increased requirement for run-around re-heating which, in turn, increases pre- cooling to enhance main cooling coil dehumidificat2on. In this way, dehumidification cycle cooling energy and re-heating energy con- sumption is reduced by a run-around pre-cool/re-heat system.
The cost for such run-around systems would be offset by the reduced cost of a smaller refrigeration system, which would be further com- plemented to by energy cost savings.
Such run-around systems may be relatively easily retrofitted to ex- isting terminal re-heat air conditioning systems to not only reduce energy consumption, but also increase available cooling capacity.
A specific embodiment of the invention will now be described by way of example with reference to an accompanying drawing.
Figure 1 shows a schematic representation of the Summer cycle of a terminal re-heat air conditioning system with a run-around pre-cool /multiple re-heat system. Figure 1A shows the Winter cycle.
Referring to the schematic drawing, the run-around coil system com- prises a pre-cool coil 1, a main cooling coil 2 and multiple termi- nal re-heat coils 3. Mixed return air and fresh air 4 is pre-cooled by cool fluid 5 counterflowirg through the upstream coil 1, which is supplied via pipework 6 from the terminal re-heat coils 3. As the cool fluid 5 counterflows through coil I, it is warmed by the air 4. The resulting warm fluid 7 is pumped via pipework 8 to the coils 3 to enable cold air 9 to be re-heated. The warm fluid 7 is, in turn, cooled as it counterflows through the coils 3 by cold air 9, which is at the temperature required by whichever humidity, or zone temperature control system has the highest cooling demand' signal. The run-around re-heat coils 3 and conventional' re-heat coils 12 are operated in sequence; and the 3-port motorised valves are controlled by the respective zone temperature control sys- tems. The pump 11 circulates fluid around the pipework loop 6 & 8 during cooling operation. Supplementary re-heat and Winter heating is provided by the re-heat coils 12 via heating pipework 13.
Figs.2 & 2A show the pre-cooling coil I in the re-circulated air stream to both give increased heat recovery for re-heat at lower ambients during a de-humidification cooling cycle, and some Winter heat recovery. Alternatively, the pre-cooling coil 1 may be located in the return air stream since such a configuration may be more practical in the case of a double decker' central station air handling unit CAHU).
Figs.3 & 3A show the pre-cooling coil 1 in the fresh air intake, which could be applied to systems having a high %age of fresh air and where the ambient temperature is mostly higher than room' tem- peratures through the year. With a resulting increased coil 1 LMTD Clog mean temperature differential) and flow temperature 7 the coil sizes and flow volumes of the run-around system would be minimised.
Figs.4, 4A & 4B show an additional pre-cooling coil Ia in the fresh air intake. This arrangement would give a similar effect to the Figs.3 & 3A arrangement, but would be applicable where the %age of fresh air is lower.
Figs.5, SR & 58 show an arrangement similar to Figure 4, although applicable to even lower %age's of fresh air.
Figures 6 & LA show a dehumidifying cooling coil 2a in the fresh air intake complete with run-around pre-cooling and re-heat coils, Ia & 2a. Having a specific dehumidifying coil in the fresh air in- take considerably reduces the amount of re-heat required during a dehumidification cycle. The run-around coils Ia & 3a also save further energy. Fig.6B shows a dehumidification cycle at lower am- bients and high humidities (e.g.circa 15 deg.C DB & 90% Rh).
Systems with a pre-cool coil la in the fresh air intake can be ex- tended to incorporate a coil lb in the exhaust air to also allow for Winter heat recovery and increased pre-cooling in Summer, as shown in Figs.7, 7A & 7B. The exhaust air may be adiabatically pre- cooled, or the exhaust air coil lb adiabatically spray cooled for a further increase in pre-cooling where the %age of fresh air is high and/or the fresh air intake temperature is particularly high.
In the case of a chilled water system it is possible to connect the pre-cooling coil I and main cooling coil 2 in series, or to in ef- fect combine the pre-cooling and main cooling coils into a single deep coil, as typically shown in Figs. 8, 8, & 8B, and operate the chillers 14 in series for further energy and cost savings. Simi- larly, the run-around 3 and 12 re-heat coils may be combined into single deep coils 3 (facilitated by incorporating a Primary-to-secondary heat exchanger 16 into the pipework circuit), as typically shown in Figs.9 8 9fl, which could reduce costs when there are many zones - although incurring an energy efficiency loss through the extra stage of heat exchange. Figure 8B shows how the addition of motorised changeover valves 15 facilitates a specific dehumidification cycle and maximises possible run-around re-heat at lower high humidity ambients. Where either the fresh air, or re- circulated air volume is low respective by-pass lines 17 or 18 should be added.
Mixing and matching of the Figures 1 to 9 arrangements may be re- quired to suit the particular requirements of any of other possible combinations of %age fresh air, ambient conditions and maximisation of re- heat requirement, etc. Control valve arrangements may also require to be varied to suit particular requirements.
Figures 10 & lOa show the cooling and heating cycles of a reverse- cycle operated main coil I that would be systematically pulsed' between these cycles during intermediate conditions. t the time of changeover it would be necessary to reverse the operation of the motorised 3-port control valves. To prevent undue temperature fluc- tuations the temperature control setpoints should be continuously re-set, and also seasonally re-set via an ambient temperature sen- sor. Self-learning computer software could also be used to auto- matically determine optimal proportional band width and setpoints.
In the case of DX refrigeration, ideally there should be two (2), or more reversible-cycle coils/systems to minimise temperature fluctuation. Variable air volume control could also be incorporated whereby at changeover to a heating cycle, the branch ducts to any zones requiring cooling would be shut-off, and vice versa - alter- natively air could be by-passed to the return air (ceiling void) for a constant volume system.
Figures 11 8 12 show typical multizone and dual-duct air condition- ing systems incorporating a run-around pre-cool/re-heat system. The coil arrangements can be varied as per some of the variations shown on other drawings, as may be required. These systems should be con- trolled such that the cold duct/deck supply air temperature is de- termined by the highest cooling (or lowest heating)'demand' control signal from any zone, or humidity control system; which would con- trol the main cooling coil. Similarly, the hot deck run-around and conventional' heater batteries would be controlled in sequence by whichever zone had the lowest cooling (or highest heating)'demand' control signal. Riternatively the hot and cold duct/deck supply air temperatures could be scheduled from ambient sensor(s).
Further possible variations would be hybrid dual-duct, or multi- zone systems having multiple conventional' terminal/zone duct re- heaters and single main run-around re-heaters.
When applied to package' air conditioning the pre-cooling coil I may be face split to match a face split main cooling coil 2, and the pre-cooling sections operated in, or out of sequence with the main cooling coil sections to either maximise latent cooling, or sensible cooling.
Where there may be other run-around systems they can possibly be connected in parallel into a single common pumped closed loop.
Since the run-around coils are likely to be relatively deep the consequent air pressure drop can be reduced when less than maximum duty is required through the use of motorised by-pass dampers, or face and by- pass dampers.
The capacity of the conventional' terminal re-heaters 12 and size of distribution pipework 13 can be minimised by also having main and frost pre-heaters that would, at least, handle the fresh air heating load.
The run-around system should be sized for a worst case of one (1) zone at maximum Summer cooling and with the other zones at their reasonable minimum cooling (maximum re-heat) requirement, i.e. fa- bric gains only plus a diversified fraction of other gains. The de- humidification re-heat sizing requirement at lower ambients (and high humidities) should also be considered, where applicable.
Where there may be zones requiring significant cooling at lower ambients, e.g.rooms with high equipment heat gains, or a shop window with high solar gains, etc., consideration should be given to pro- viding terminal coaling coils, or fan coil units to such zones.
Where there may be two (2) chillers, or condensing units they could be arranged such that the 1st stage unit is water cooled providing condenser heat to the supplementary conventional' re-heaters, and the 2nd stage unit is a heat pump providing for Winter heating. The run-around system could also be extended to include coil(s) in con- denser air discharges to recover heat for dehumidification cycle supplewentary re-heat, although requiring extra deep run-around re- heat coils to also maintain a pre-cooling effect. Similarly, the run- around system could include dry cooling' coils to allow for free-cooling' in cool weather; with the action of the run-around re-heat' coil control valves reversed.

Claims (1)

  1. CLA 1MB 1) A re-heat air conditioning (A/C) system having a main cooling
    coil (controlled by zone temperature control systems) and a run- -around pre-cooling coil that exchanges energy with multiple run- around re-heat coils located upstream of conventional' re-heater batteries, and operated in sequence with them by their respective zone temperature control systems.
    2) A re-heat A/C system according to Claim 1, in which the control of the main cooling coil may be scheduled via ambient sensor(s).
    3) A re-heat A/C system according to Claim 1, or 2 in which control of the main cooling coil may be overridden by, or be by a direct, or indirect form of relative humidity control system.
    4) A re-heat A/C system according to Claim 1, 2 or 3, in which there may also be a run-around coil located in the fresh airflow.
    5) A re-heat A/C system according to Claim 4, in which there may be a cooling coil located downstream of the fresh air run-around coil.
    6) A re-heat A/C system according to Claim 5, in which there may be a runaround coil located downstream of the fresh air cooling coil.
    7) A re-heat A/C system according to any preceding Claim, in which a precool coil located in front of a face split main cooling coil may also be face split.
    8) A re-heat A/C system according to any preceding Claim, in which the pre-cooling coil(s) and cooling coil(s) may be combined, or where these coils may be separate they may be incorporated into the same fluid circuit.
    9) A re-heat A/C system according to any preceding Claim, in which the run-around and conventional' re-heat coil(s) may be combined, or where these coils may be separate they may be incorporated into the same fluid circuit.
    10) A re-heat A/C system according to any preceding Claim, in which the flow of fluids and/or air through any of the coils may be con- trolled to obtain a respective required function.
    11) A re-heat A/C system according to any preceding Claim, in which the run-around system, or fluid circuit may incorporate heat ex- change coil(s) in the exhaust air system(s), and wherein they may be operated to recover heat energy.
    11) A re-heat A/C system according to any preceding Claim, in which the run-around system, or fluid circuit may incorporate heat ex- change coil(s) in the refrigeration condenser exhaust air system(s) 12) A re-heat A/C system according to any preceding Claim, in which the run-around system, or fluid circuit may incorporate dry- cooler' coal(s).
    13) A re-heat A/C system according to Claim 10, in which the ex- haust air coil(s) may be adiabatically spray cooled, or the exhaust air may be adiabatically pre-cooled.
    14) A re-heat A/C system according to any preceding Claim, in which the main cooling coil may be reverse-cycled into a heating mode, and wherein there is no conventional' terminal re-heat system, or wherein a main cooling coil and heater battery may be cycled.
    15) A re-heat A/C system according to Claim 13, in which the air volume may be variable with the zone branch ducts having automatic shut-off dampers, or may be non-variable and also have automatic by-pass dampers operating in sequence with the shut-off dampers.
    16) A re-heat A/C system according to any preceding Claim, in which there may only be a single run-around re-heater coil controlled by the zone temperature control systems, or scheduled via ambient sensor(s) - 17) A re-heat A/C system according to Claim 15, in which there may be a single conventional' re-heater battery operating in sequence with the run- around re-heater coil and similarly controlled.
    18) A re-heat A/C system according to any preceding Claim, in which the run-around system may be connected via a common closed loop pipework circuit to other run-around systems.
    19) A re-heat A/C system according to any preceding Claim, in which the main' cooling coil may comprise more than one (1) coil, or multiple coil sections.
    I
    Amendments to the claims have been filed as follows CLP 1MG I) P conventional terminal re-heat air conditioning system (i.e. the main cooling coil is controlled by whichever zone temperature control system has the highest cooling demand' signal) plus a run- around pre-cooling coil that exchanges energy with multiple run- around re-heat coils located upstream of the conventional re-heater batteries, and operated in sequence with them by their respective zone temperature control systems.
    a) n terminal re-heat system according to Claim I, wherein the con- trol of the main cooling coil may be overridden by a relative humi- dity control system, either directly, or indirectly sensed.
    3) P terminal re-heat system according to Claim 1, or 2, wherein there is also a run-around coil located in the fresh air stream.
    4) P terminal re-heat system according to Claim 3, wherein there i.
    a cooling coil located downstream of the fresh air run-around ccil.
    5) P terminal re-heat system according to Claim 4, wherein there is a further run-around coil located downstream of the fresh air cool- ing coil.
    6) P terminal re-heat system according to any preceding Claim, wherein a pre-cool coil located in front -of a face split main cool- ing coil may also be face split.
    7) P terminal re-heat system according to any preceding Claim, - wherein the pre-cooling coil(s) and cooling coil(s) are combined, or where these coils are separate they are incorporated into the same chilled fluid circuit.
    8) P terminal re-heat system according to any preceding Claim, wherein the flow of fluids and/or air through any of the coils is controlled to obtain the respective required function.
    9) P terminal re-heat system according to any preceding Claim, wherein the run-around system incorporates a heat exchange coil(s) in the exhaust air system(s), and wherein the run-around system may also be operated to recover heat energy, including refrigeration system heat of rejection.
    10) P terminal re-heat system according to Claim 9, wherein the ex- haust coil(s) may be adiabatically spray cooled, or the exhaust air may be adiabatically pre-cooled.
    11) P terminal re-heat system according to any preceding Claim, wherein the main cooling coil may be reverse cycle operated and there is no conventional terminal re-heat system.
    12) fl terminal re-heat system according to any preceding Claim, wherein the run-around system may be connected via a common closed loop pipework circuit to other run-around systems.
    13) R terminal re-heat system according to any preceding Claim, wherein the main cooling coil may comprise more than one (1) coil.
GB0522927A 2005-07-22 2005-11-10 A re-heat air conditioning system Withdrawn GB2428470A (en)

Applications Claiming Priority (8)

Application Number Priority Date Filing Date Title
GB0515044A GB0515044D0 (en) 2005-07-22 2005-07-22 An advanced multi-zone terminal re-heater control air conditioning system
GB0515366A GB0515366D0 (en) 2005-07-27 2005-07-27 An advanced multi-zone terminal re-heat air conditioning system
GB0515600A GB0515600D0 (en) 2005-07-22 2005-07-29 An advanced terminal re-heat air conditioning system
GB0516047A GB0516047D0 (en) 2005-07-22 2005-08-04 An advanced terminal re-heat air conditioning system
GB0516847A GB0516847D0 (en) 2005-07-22 2005-08-17 An advanced terminal re-heat air conditioning system
GB0518824A GB0518824D0 (en) 2005-07-22 2005-09-15 An advanced terminal re-heat air conditioning system
GB0520537A GB0520537D0 (en) 2005-07-22 2005-10-08 An advanced terminal re-heat air conditioning system
GB0521773A GB0521773D0 (en) 2005-07-22 2005-10-26 Advanced re-heat air conditioning systems

Publications (2)

Publication Number Publication Date
GB0522927D0 GB0522927D0 (en) 2005-12-21
GB2428470A true GB2428470A (en) 2007-01-31

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WO2012102996A1 (en) * 2011-01-28 2012-08-02 Trane International Inc. Wear-leveling for components of an auxiliary heat source
CN103256666A (en) * 2013-05-15 2013-08-21 天津中德职业技术学院 Independent primary air system provided with heat pipe exchanger and working method thereof
CN103363608A (en) * 2013-07-23 2013-10-23 于向阳 Fresh air unit with direct evaporative cooler and passive cooling air conditioning device of fresh air unit
CN103398431A (en) * 2013-07-23 2013-11-20 于向阳 Distributed fresh air supply air-conditioning method and air conditioner
US9404669B2 (en) 2012-10-04 2016-08-02 Carrier Corporation Application of electric heat coil in fan unit
WO2019085443A1 (en) * 2017-10-31 2019-05-09 江苏天舒电器有限公司 Self-adaptive and self-regulating heat pump-based hot blast stove control system and control method thereof
FR3091334A1 (en) * 2018-12-28 2020-07-03 Franck Buchner Energy transfer in the same air handling unit for temperature and hygrometry regulation

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US5400607A (en) * 1993-07-06 1995-03-28 Cayce; James L. System and method for high-efficiency air cooling and dehumidification
US5448897A (en) * 1991-05-09 1995-09-12 Heat Pipe Technology, Inc. Booster heat pipe for air-conditioning systems
WO2005121650A1 (en) * 2004-06-08 2005-12-22 Peter John Bayram An ‘installed’ air conditioning cooling capacity reduction run-around pre-cool / re-heat coil system

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Publication number Priority date Publication date Assignee Title
US5448897A (en) * 1991-05-09 1995-09-12 Heat Pipe Technology, Inc. Booster heat pipe for air-conditioning systems
US5400607A (en) * 1993-07-06 1995-03-28 Cayce; James L. System and method for high-efficiency air cooling and dehumidification
WO2005121650A1 (en) * 2004-06-08 2005-12-22 Peter John Bayram An ‘installed’ air conditioning cooling capacity reduction run-around pre-cool / re-heat coil system

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012102996A1 (en) * 2011-01-28 2012-08-02 Trane International Inc. Wear-leveling for components of an auxiliary heat source
US8967490B2 (en) 2011-01-28 2015-03-03 Trane International Inc. Wear-leveling for components of an auxiliary heat source
US9163843B2 (en) 2011-01-28 2015-10-20 Trane International Inc. Wear-leveling for components of an auxiliary heat source
US9404669B2 (en) 2012-10-04 2016-08-02 Carrier Corporation Application of electric heat coil in fan unit
CN103256666A (en) * 2013-05-15 2013-08-21 天津中德职业技术学院 Independent primary air system provided with heat pipe exchanger and working method thereof
CN103363608A (en) * 2013-07-23 2013-10-23 于向阳 Fresh air unit with direct evaporative cooler and passive cooling air conditioning device of fresh air unit
CN103398431A (en) * 2013-07-23 2013-11-20 于向阳 Distributed fresh air supply air-conditioning method and air conditioner
WO2019085443A1 (en) * 2017-10-31 2019-05-09 江苏天舒电器有限公司 Self-adaptive and self-regulating heat pump-based hot blast stove control system and control method thereof
FR3091334A1 (en) * 2018-12-28 2020-07-03 Franck Buchner Energy transfer in the same air handling unit for temperature and hygrometry regulation

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