Refrigeration – Atmosphere and sorbent contacting type
Reexamination Certificate
2000-04-24
2001-12-04
Doerrler, William (Department: 3744)
Refrigeration
Atmosphere and sorbent contacting type
C062S096000
Reexamination Certificate
active
06324860
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an air-conditioning system which employs a desiccant, and more particularly to an air-conditioning system which employs a heat pump as a heat source for heating regenerating air and cooling processing air.
BACKGROUND ART
FIG. 11
of the accompanying drawings shows an air-conditioning system comprising a combination of an absorption heat pump (
200
: represented by HP) as a heat source and an air-conditioning unit employing a desiccant, i.e., a so-called desiccant air-conditioning unit.
The air-conditioning system comprises an air-conditioning unit having a path A for processing air from which moisture has been adsorbed by a desiccant wheel
103
, a path B for regenerating air which is heated by a heat source and thereafter passes through the desiccant wheel
103
that has adsorbed the moisture in order to desorb the moisture from the desiccant, and an air-conditioning unit having a sensible heat exchanger
104
between the processing air from which moisture has been adsorbed and the regenerating air to be regenerated by the desiccant wheel
103
and heated by the heat source, and a heat pump
200
. The regenerating air of t he air-conditioning unit is heated by a heater
120
using the high temperature heat source of the heat pump
200
as a heating source, for thereby regenerating the desiccant, and the processing air of the air-conditioning unit is cooled by a cooler
115
using the low temperature heat source of the heat pump as a cooling heat source.
The air-conditioning system is arranged such that the heat pump simultaneously cools the processing air and heats the regenerating air of the desiccant air-conditioning unit. Based on drive energy applied to the heat pump from an external source, the heat pump produces an effect of cooling the processing air. The desiccant is regenerated by the sum of the heat removed from the processing air by the operation of the heat pump and the drive energy applied to the heat pump. Therefore, the drive energy applied from the external source is utilized in multiple ways for a high energy-saving effect.
If a motor-operated heat pump, e.g., a vapor compression heat pump, is used as the heat source of the air-conditioning unit, then it is proposed to add a thermal storage device to the air-conditioning unit for the purposes of reducing electricity consumption in summer days and saving the operation cost based on the use of inexpensive midnight power services, as in the general case of the conventional air-conditioning systems.
FIG. 12
of the accompanying drawings shows an air-conditioning system which is a combination of a heat source assembly including a built-in thermal storage device and a so-called desiccant air-conditioning unit, constructed based on the conventional arrangement.
As shown in
FIG. 12
, a heat source assembly
300
with a thermal storage function has a high-temperature thermal storage tank
310
for heating regenerating air and a low-temperature thermal storage tank
330
for cooling processing air. For thermal storage operation at night, a heat pump
200
, a heating medium circulatory system, and a chilling medium circulatory system are operated to remove heat from the low-temperature thermal storage tank
330
and transfer the heat to the high-temperature thermal storage tank
310
for simultaneously storing cooling effect and heating effect. The heat pump
200
comprises a compressor
360
, a condenser
320
, an expansion valve
350
, and an evaporator
340
. The hearing medium circulatory system comprises a pump
312
, a path
314
, the condenser
320
, a path
314
, the high-temperature thermal storage tank
310
, and a path
311
. The chilling medium circulatory system comprises a pump
332
, a path
333
, the evaporator
340
, a path
334
, the low-temperature thermal storage tank
330
, and a path
331
. For air-conditioning operation using thermal storage stored in daytime, a heating medium circulatory system for the air-conditioning unit and a chilling medium circulatory system for the air-conditioning unit are operated, in addition to the heat pump and the chilling and heating medium circulatory systems for the heat sources. The heating medium circulatory system for the air-conditioning unit comprises a pump
315
, a path
316
, the high-temperature thermal storage tank
310
, a path
122
, a heater
120
, and a path
123
. The chilling medium circulatory system for the air-conditioning unit comprises a pump
335
, a path
336
, the low-temperature thermal storage tank
330
, a path
117
, a cooler
115
, and a path
118
. By using both of the stored cooling effect and the stored heating effect for a portion of the air-conditioning load, air-conditioning operation can be achieved while saving electric energy in daytime. Since both of the cooling effect and heating effect can be stored simultaneously at night, the air-conditioning system discharges no heat whatsoever into the atmosphere thereby to prevent thermal pollution, i.e., prevent the city from becoming a heat island at night.
However, in order to achieve a desiccant air-conditioning cycle under standard air-conditioning conditions in summer as indicated by the psychrometric chart shown in
FIG. 13
of the accompanying drawings, a temperature difference is needed to transfer heat in the heat exchangers and the thermal storage tanks. It is necessary that the higher heat source temperature be higher than the temperature of the regenerating air prior to the regeneration of the desiccant (state T: 70° C.), and that the lower heat source temperature be lower than the temperature of the processing air prior to the humidifier (state N: 19° C.). Therefore, a problem arises in that a temperature lift in the heat pump during the thermal storage operation becomes abnormally high.
An example will be described below.
An air cycle of the desiccant air-conditioning operation is formed under summer meteorological conditions by making the following state changes: Air in an air-conditioned room
101
(processing air: state K: 27° C., 10.8 k/kg) is drawn via a path
107
by a fan
102
, increased in pressure, and supplied via a path
108
to the desiccant wheel
103
where moisture in the air is adsorbed by an absorbent such as silica gel, the humidity ratio of the air is lowered, and the temperature of the air is increased by the heat of adsorption (state L; 45° C., 5.8 g/kg). The air whose humidity is lowered and temperature is increased is sent via a path
109
to the sensible heat exchanger
104
where the air is cooled by a heat exchange with outside air (regenerating air) (state M: 33° C.). The cooled air is delivered via a path
110
to the chilled water heat exchanger (cooler)
115
which further cools the air (state N: 19° C.). The cooled air is then delivered via a path
111
to a humidifier
105
where the temperature of the air is lowered in an isenthalpic process by the way of water injection or evaporative cooling (state P), after which the air is returned as supply air via a path
112
to the air-conditioned room
101
. In this manner, an enthalpic difference &Dgr;Q is developed between the return air (state K) and the supplied air (state P) in the room, thus cooling the air-conditioned room
101
. The desiccant is regenerated as follows: Outside air for regenerating (OA: state Q: 30° C., 19 g/kg) is drawn via a path
124
by a fan
140
, increased, in pressure, and supplied to the sensible heat exchanger
104
where the regenerating air cools the processing air and is increased in temperature (state R: 42° C.). The regenerating air thus flows via a path
125
into a next sensible heat exchanger
121
in which the regenerating air is increased in temperature by a heat exchange with high-temperature air that has regenerated the desiccant (state S: 50° C.). The regenerating air which has left the sensible heat exchanger
121
flows via a path
126
into the hot water heat exchanger (heater)
120
where the regenerating air is heated by hot water with its temperature increased to 70° C. and relative humidity
Inaba Hideo
Maeda Kensaku
Armstrong Westerman Hattori McLeland & Naughton LLP
Doerrler William
Ebara Corporation
Jiang Chen-Wen
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