JP3902912B2

JP3902912B2 - Control device

Info

Publication number: JP3902912B2
Application number: JP2000307980A
Authority: JP
Inventors: 英一榎本; 雅裕古川; 靖治黒木; 裕嗣石野; 茂川崎
Original assignee: Sanyo Electric Co Ltd; Tokyo Gas Co Ltd
Current assignee: Sanyo Electric Co Ltd; Tokyo Gas Co Ltd
Priority date: 2000-10-06
Filing date: 2000-10-06
Publication date: 2007-04-11
Anticipated expiration: 2020-10-06
Also published as: JP2002115927A

Description

【０００１】
【発明の属する技術分野】
本発明は吸収式冷凍機の制御装置に係わるものである。
【０００２】
【従来の技術】
地球環境問題の高まりと共に、省エネルギー性向上に対する要求は益々高まってきている。そして、空調システムにおいても、省エネ法の改正により空調エネルギー消費係数の基準が強化されるなど、一層の高効率化が求められている。
【０００３】
しかし、吸収式冷凍機においては運転が安全に継続されることを最大の眼目に制御仕様を決定している。それは冷却水流量が減少すると、高温再生器の圧力上昇と温度上昇が起こるので、省エネを図る場合にも高温再生器の温度・圧力に影響を及ぼす冷却水出口温度を監視して、絞ったりするのが一般的であった。
【０００４】
また、運転負荷に関係付けられる高温再生温度を用いて、その温度が低い場合は冷却水流量を減少させ、温度上昇に伴って冷却水流量を増加させるなどの方法が採られてきた。また、起動運転時・稀釈運転時には、定流量（定格）運転する方法が一般的であった。
【０００５】
【発明が解決しようとする課題】
しかし、吸収式冷凍機においては冷却水流量を絞ることで吸収器と凝縮器の効率が低下し、再生器に供給する熱量（天然ガスなどを燃焼させ、その熱を利用して吸収液を加熱し、冷媒を蒸発分離して吸収液の再生を図る場合はその燃料消費量）が増加する。すなわち、冷却水流量を絞ることで冷却水ポンプを運転するための電力消費量は削減できるが、燃料消費量は逆に増加するので、冷却水ポンプ運転のための電力消費量と燃料消費量の両方を考量してランニングコストの削減を図るに必要があり、さらに起動から稀釈・停止に至る全領域に渡ってランニングコストを削減することが求められていた。
【０００６】
【課題を解決するための手段】
本発明は上記従来技術の課題を解決するための具体的手段として、高温再生器に供給する熱量を制御する制御信号と、吸収器と凝縮器に冷却水を供給する冷却水ポンプを制御する制御信号とを出力する機能を備えた吸収式冷凍機の制御装置において、吸収式冷凍機の起動から所定時間が経過するまで、あるいは高温再生器における温度または圧力が所定値に上昇するまでは、定格より少ない一定量の冷却水を供給するための制御信号を前記冷却水ポンプに出力し、且つ、前記吸収式冷凍機の起動から所定時間が経過する、あるいは前記高温再生器における温度または圧力が所定値に上昇する、の何れかが起こると共に、前記高温再生器に供給する熱量が前記所定時間より短い他の所定時間に渡って設定値以下であるときは、前記冷却水ポンプを運転する電力変動費と前記高温再生器に供給する熱量の燃料変動費の和が最低となる前記冷却水の定格に対する流量比率を算出するために予め定めた演算式に基づいて算出した冷却水流量を得るように、前記冷却水の流量を変動制御する制御信号を前記冷却水ポンプに出力することを特徴とするものである。
【００１０】
【発明の実施の形態】
以下、本発明の実施形態を図面に基づいて詳細に説明する。
図２は冷媒に例えば水、吸収液（溶液）に臭化リチウム（ＬｉＢｒ）溶液を用いた吸収式冷凍機である吸収冷温水機の概略構成図であり、１は蒸発器、２は吸収器、３は例えばガスバーナ４によって加熱される高温再生器、５は低温再生器、６は凝縮器、７は吸収器２から高温再生器３に流れる濃度の薄い吸収液と低温再生器５から吸収器２に流れる濃度の濃い吸収液とを熱交換する溶液熱交換器である低温熱交換器、８は吸収器２から低温熱交換器７を経て高温再生器３に流れる稀吸収液と高温再生器３から低温再生器５に流れる中間濃度の吸収液とを熱交換する溶液熱交換器である高温熱交換器、１１〜１５は吸収液配管、１６は吸収液ポンプ、１７〜１９は冷媒配管、２０は冷媒ポンプ、２１はガスバーナ４に接続したガス配管、２２は加熱量制御弁、２３は途中に蒸発器熱交換器２４が設けられた冷温水配管、２５は途中に冷却水ポンプ２６と吸収器熱交換器２７と凝縮器熱交換器２８とが設けられた冷却水配管であり、それぞれは図２に示したように配管接続されている。
【００１１】
また、２９は蒸発器１の冷媒液溜り３０と吸収器２の吸収液溜り３１とを配管接続する冷媒バイパス管、３２は開閉弁、３３は吸収液配管１２と吸収器２とを接続する吸収液バイパス管、３４は開閉弁、３５は冷媒配管１７と吸収器２とを接続する冷媒蒸気バイパス管、３６は開閉弁であり、それぞれ図のように接続され、各開閉弁３２・３４・３６は冷水の供給時に閉じ、温水の供給時に開く。
【００１２】
また、３７は冷却水ポンプ２６に加える電力を所望の周波数に変換する周波数変換装置、３８は冷温水配管２３の蒸発器１入口側に設置されて冷水の流入温度Ｔ１を検出する温度検出手段、３９は冷温水配管２３の蒸発器１出口側に設置されて冷水の流出温度Ｔ２を検出する温度検出手段、４０は冷却水配管２５の吸収器２入口側に設置されて冷却水の流入温度Ｔ３を検出する温度検出手段、４１は高温再生器３に設置されて器内で加熱されている吸収液の温度Ｔ４を検出する温度検出手段である。
【００１３】
５０は、マイクロコンピュータなどを備えて構成される制御装置であり、前記温度検出手段３８〜４１より温度信号を入力して、高温再生器３に投入する熱量と冷却水配管２５を流れる冷却水の流量とを制御する。
【００１４】
以下、制御装置５０の構成を図１に基づいて説明する。５１は温度検出手段３８〜４１などからの検出信号を入力し、信号変換して中央演算処理手段５２へ出力する入力手段、５３は制御プログラムなどを記憶している記憶手段、５４は適宜の制御条件、例えば冷却水ポンプ２６に加える電力周波数の最低周波数、冷却水ポンプ２６に加える電力周波数の変化速度などを設定することのできる設定入力手段、５５はガスバーナ４の火力を制御するために、温度検出手段３９が検出する冷水の温度Ｔ２に基づいて実行する中央演算処理手段５２の演算結果を受けて加熱量制御弁２２に所要の制御信号を出力するための容量制御出力手段、５６は吸収器熱交換器２７と凝縮器熱交換器２８に冷却水を供給する冷却水ポンプ２６の回転数を制御するために、中央演算処理手段５２の演算結果を受けて周波数変換装置３７などに所要の制御信号を出力する外部出力手段である。
【００１５】
制御装置５０の記憶手段５３には、図３に示した起動時における高温再生温度、すなわち温度検出手段４１が検出する高温再生器３の内部で加熱されている吸収液の温度Ｔ４と、変換して冷却水ポンプ２６に加える電力周波数を決定するための関係式を記憶してある。
【００１６】
そして、吸収式冷凍機の起動時においては、中央演算処理手段５２は温度検出手段４１が検出した吸収液の温度Ｔ４と、記憶手段５３に記憶した図３の関係式に基づいて、冷却水ポンプ２６に加える電力周波数を決定し、周波数変換装置３７により冷却水ポンプ２６に加えている電力の周波数をその周波数に変換して、冷却水ポンプ２６の回転数を制御する。
【００１７】
すなわち、吸収式冷凍機の起動時においては、中央演算処理手段５２は温度検出手段４１が検出した吸収液の温度Ｔ４が所定の低温度、例えば８０℃以下であるときには、冷却水ポンプ２６には所定の最低周波数、例えば３０Ｈｚに変換した電力を加えて冷却水ポンプ２６を最低の回転数で運転し、温度検出手段４１が所定の高温度、例えば１４０℃以上を検出したときには所定の最高周波数、例えば６０Ｈｚに変換した電力を冷却水ポンプ２６に加えて冷却水ポンプ２６を最高の回転数で運転し、温度検出手段４１が所定の低温度と高温度との間の温度を検出したときには、３０〜６０Ｈｚの間で直線的に変換した電力を冷却水ポンプ２６に加えてその回転数を直線的に制御するように設けてある。そして、このときの制御フローは、図４のように表される。
【００１８】
また、制御装置５０の記憶手段５３には、吸収式冷凍機の起動から所定時間、例えば３０分が経過すると共に、加熱量制御弁２２の開度が所定時間、例えば５分間に渡って設定値、例えば定格の８０％以下であるときには、冷却水ポンプ２６を運転するために消費する電力変動費と、ガスバーナ４で消費する燃料変動費との和が最低になる冷却水の定格に対する流量比率を、運転負荷と、温度検出手段４０が検出した冷却水の流入温度Ｔ３に基づいて演算算出するために、予備試験などにより定めた演算式を記憶すると共に、その演算式に基づいて算出した冷却水の流量を得るために、周波数変換装置３７により周波数変換した電力が冷却水ポンプ２６に加えられて、冷却水が変動制御されるようにしてある。そして、このときの制御フローは、図５のように表される。
【００１９】
また、中央演算処理手段５２は吸収式冷凍機の運転停止信号が入力されたときには、図６に示したようにその運転停止信号が入力されたときに冷却水ポンプ２６に加えていた電力周波数を所定時間、例えば１０分間に渡って冷却水ポンプ２６に加え続けて吸収液を稀釈する運転を行うようにしてある。そして、このときの制御フローは、図７のように表される。
【００２０】
上記構成の吸収式冷凍機による冷水供給運転においては、従来と同様に高温再生器３で蒸発した冷媒は低温再生器５を経て凝縮器６へ流れ、冷却水ポンプ２６によって凝縮器熱交換器２８を流れる冷却水と熱交換して凝縮したのち冷媒配管１８を介して蒸発器１へ流れる。そして、冷媒が蒸発器熱交換器２４を流れる水と熱交換して蒸発し、気化熱によって蒸発器熱交換器２４を流れる水が冷却される。そして、冷水が図示しない負荷に循環して冷房作用などを行う。
【００２１】
また、蒸発器１で蒸発した冷媒は、冷却水ポンプ２６によって吸収器熱交換器２７を流れる冷却水により冷却されている吸収器２で吸収液に吸収される。冷媒を吸収して濃度が薄くなった稀吸収液が吸収液ポンプ１６の運転によって低温熱交換器７および高温熱交換器８を経て高温再生器３へ送られる。高温再生器３へ送られた吸収液はバーナ４によって加熱されて冷媒が蒸発し、中濃度の吸収液が高温熱交換器８を経て低温再生６へ流れる。低温再生器５で吸収液は高温再生器８から冷媒配管１７を流れてきた冷媒蒸気によって加熱され、さらに冷媒蒸気が分離され濃度が高くなる。高濃度になった吸収液は低温熱交換器７を経て温度低下して吸収器２へ送られて散布される。
【００２２】
そして、上記吸収式冷凍機の冷却水ポンプ２６は、本発明の制御装置５０により起動時には最低の回転数で運転され、温度検出手段４１が検出する高温再生器３内の吸収液の温度Ｔ４の上昇と共にその回転数は上げられるので、吸収液の温度上昇が十分でない起動時から冷却水ポンプ２６を定格運転する従来技術より、ランニングコストの削減が図れる。
【００２３】
また、起動から所定時間が経過し、機内の圧力および温度が十分に安定した状態で、加熱量制御弁２２の開度が小さい状態が所定時間に渡って継続するときには、運転負荷が小さいと判断して冷却水ポンプ２６の回転数が絞られるので、この場合も冷却水ポンプ２６を定格運転する従来技術より、ランニングコストの削減が図れる。なお、機内の圧力および温度が十分に安定するのを待って、部分負荷であるか否かを判定するので、その判定を誤ることがない。
【００２４】
さらに、吸収式冷凍機の運転を停止するときには、冷却水ポンプ２６はその運転停止信号が入力されたときの回転数で所定時間運転が継続され、これにより吸収液の稀釈が行われる。
【００２５】
そのため、運転負荷が小さいためにガスバーナ４による加熱が少なく、したがって吸収液の濃度も、温度検出手段４１が検出する吸収液の温度Ｔ４も低く、冷却水をそれほど循環しなくても吸収液が結晶化する心配がないときには、ポンプ２６の運転を温度検出手段４１が検出する吸収液の低い温度Ｔ４に基づいて、あるいは温度検出手段３８、３９、４０が検出する温度Ｔ１、Ｔ２、Ｔ３に基づいて算出された低い周波数の電力を冷却水ポンプ２６に加えて、定格より少ない回転数で冷却水ポンプ２６を運転するので、吸収液の濃度と温度に無関係に冷却水ポンプ２６を定格運転して稀釈する従来技術より、ランニングコストの削減が図れる。
【００２６】
なお、本発明は上記実施形態に限定されるものではないので、特許請求の範囲に記載の趣旨から逸脱しない範囲で各種の変形実施が可能である。
【００２７】
例えば、前記した起動時の制御、すなわち温度検出手段４１が検出する吸収液の温度Ｔ４が所定の８０℃と云った低温度を検出するまで、冷却水ポンプ２６を最低の回転数で運転し、その後吸収液の温度Ｔ４の上昇と共に冷却水ポンプ２６の回転数を上げる制御に代えて、高温再生器３内の圧力を検出し、その圧力に基づいて冷却水ポンプ２６の回転数を制御するようにしても良いし、所定時間が経過するまでは冷却水ポンプ２６を所定の最低回転数で制御し、その所定時間が経過した後、温度検出手段４１が検出する吸収液温度Ｔ４や、高温再生器３内の圧力に基づいて冷却水ポンプ２６の回転数を制御するようにしても良い。
【００２８】
また、吸収式冷凍機としては、高温再生器３内の吸収液を加熱するガスバーナ４に代えて、高温の蒸気などを供給して吸収液を加熱するものであっても良い。
【００２９】
また、制御装置５０により運転が制御される冷却水ポンプ２６としては、極数変換によりその回転数が制御されて吸収器熱交換器２７、凝縮器熱交換器２８に供給する冷却水の流量を制御するタイプのポンプであっても良いし、並列に複数台が設置され、運転する台数が制御されて吸収器熱交換器２７、凝縮器熱交換器２８に供給する冷却水の流量を制御するようにしたものであっても良い。
【００３０】
また、前記実施形態においては冷水あるいは温水を供給できる構成の吸収式冷凍機に基づいて説明したが、冷水のみを供給する吸収式冷凍機であっても良い。
【００３１】
【発明の効果】
以上説明したように、請求項１の制御装置によれば、冷却水ポンプは吸収式冷凍機の起動時には最低の回転数で運転され、高温再生器の吸収液の温度上昇と共にその回転数は上げられるので、吸収液の温度上昇が十分でない起動時から冷却水ポンプを定格運転する従来技術より、ランニングコストの削減が図れる。
【００３２】
また、この制御装置によれば、運転負荷が小さいときには冷却水ポンプの回転数が絞られるので、この場合も冷却水ポンプを運転負荷に無関係に定格運転する従来技術より、ランニングコストの削減が図れる。
【図面の簡単な説明】
【図１】本発明の制御装置の一構成例を示す説明図である。
【図２】本発明の制御装置で制御する吸収式冷凍機の構成を示す説明図である。
【図３】吸収式冷凍機を起動する際に冷却水ポンプに加える電力周波数を示す説明図である。
【図４】制御フローを示す説明図である。
【図５】制御フローを示す説明図である。
【図６】吸収式冷凍機を停止する際に冷却水ポンプに加える電力周波数を示す説明図である。
【図７】制御フローを示す説明図である。
【符号の説明】
１蒸発器
２吸収器
３高温再生器
４ガスバーナ
５低温再生器
６凝縮器
７低温熱交換器
８高温熱交換器
１１・１２・１３・１４・１５吸収液配管
１６吸収液ポンプ
１７・１８・１９冷媒配管
２０冷媒ポンプ
２１ガス配管
２２加熱量制御弁
２３冷温水配管
２４蒸発器熱交換器
２５冷却水配管
２６冷却水ポンプ
２７吸収器熱交換器
２８凝縮器熱交換器
２９冷媒バイパス管
３０冷媒液溜り
３１吸収液溜り
３２開閉弁
３３吸収液バイパス管
３４開閉弁
３５冷媒蒸気バイパス管
３６開閉弁
３７周波数変換装置
３８・３９・４０・４１温度検出手段
５０制御装置
５１入力手段
５２中央演算処理手段
５３記憶手段
５４設定入力手段
５５容量制御出力手段
５６外部出力手段[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device for an absorption refrigerator.
[0002]
[Prior art]
As global environmental problems increase, the demand for improved energy savings is increasing. Also in air conditioning systems, higher efficiency is required, for example, the standard of air conditioning energy consumption coefficient is strengthened by amendment of the Energy Saving Law.
[0003]
However, in the absorption chiller, the control specification is determined with the greatest eye that the operation is continued safely. When the cooling water flow rate decreases, the pressure and temperature of the high-temperature regenerator increase. Therefore, when saving energy, the cooling water outlet temperature that affects the temperature and pressure of the high-temperature regenerator is monitored and throttled. It was common.
[0004]
In addition, a method has been adopted in which a high temperature regeneration temperature related to the operation load is used, and when the temperature is low, the cooling water flow rate is decreased and the cooling water flow rate is increased as the temperature rises. In addition, a constant flow rate (rated) operation method is generally used during start-up operation and dilution operation.
[0005]
[Problems to be solved by the invention]
However, in the absorption chiller, the efficiency of the absorber and the condenser is reduced by reducing the cooling water flow rate, and the amount of heat supplied to the regenerator (combustion of natural gas etc. is used to heat the absorption liquid) However, when the refrigerant is evaporated and separated to regenerate the absorbing liquid, the fuel consumption thereof increases. In other words, the power consumption for operating the cooling water pump can be reduced by reducing the cooling water flow rate, but the fuel consumption increases conversely, so the power consumption and fuel consumption for the cooling water pump operation can be reduced. It is necessary to consider both of them to reduce the running cost, and further, it has been required to reduce the running cost over the entire range from starting to dilution and stopping.
[0006]
[Means for Solving the Problems]
The present invention provides a control signal for controlling the amount of heat supplied to the high-temperature regenerator and a control for controlling the cooling water pump for supplying cooling water to the absorber and the condenser as specific means for solving the above-described problems of the prior art. In a control device for an absorption chiller with a function to output a signal, the rating is applied until a predetermined time has elapsed since the start of the absorption chiller, or until the temperature or pressure in the high-temperature regenerator rises to a predetermined value. A control signal for supplying a smaller amount of cooling water is output to the cooling water pump, and a predetermined time has elapsed since the start of the absorption chiller, or the temperature or pressure in the high temperature regenerator is predetermined. And when the amount of heat supplied to the high-temperature regenerator is equal to or less than a set value for another predetermined time shorter than the predetermined time, the cooling water pump Cooling water flow rate calculated based on a predetermined arithmetic expression for calculating a flow rate ratio with respect to the cooling water rating at which the sum of the operating power fluctuation cost and the fuel fluctuation cost of the amount of heat supplied to the high temperature regenerator is minimum In order to obtain the above, a control signal for controlling the flow rate of the cooling water is output to the cooling water pump.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 2 is a schematic configuration diagram of an absorption chiller / heater that is an absorption refrigerator using, for example, water as a refrigerant and a lithium bromide (LiBr) solution as an absorption liquid (solution), where 1 is an evaporator and 2 is an absorber. 3 is a high-temperature regenerator heated by, for example, a gas burner 4, 5 is a low-temperature regenerator, 6 is a condenser, 7 is an absorbent having a low concentration flowing from the absorber 2 to the high-temperature regenerator 3, and an absorber from the low-temperature regenerator 5. 2 is a solution heat exchanger for exchanging heat with a dense absorbent flowing in 2, and 8 is a rare absorbent and high temperature regenerator flowing from the absorber 2 to the high temperature regenerator 3 via the low temperature heat exchanger 7. 3 is a high-temperature heat exchanger that is a solution heat exchanger that exchanges heat with an intermediate concentration absorbing liquid flowing from the low-temperature regenerator 5, 11 to 15 is an absorbing liquid pipe, 16 is an absorbing liquid pump, and 17 to 19 are refrigerant pipes, 20 is a refrigerant pump, 21 is a gas pipe connected to the gas burner 4, 22 A heating amount control valve, 23 is a cold / hot water pipe provided with an evaporator heat exchanger 24, and 25 is provided with a cooling water pump 26, an absorber heat exchanger 27, and a condenser heat exchanger 28. The cooling water pipes are connected to each other as shown in FIG.
[0011]
Also, 29 is a refrigerant bypass pipe that pipe-connects the refrigerant liquid reservoir 30 of the evaporator 1 and the absorption liquid reservoir 31 of the absorber 2, 32 is an on-off valve, and 33 is an absorption that connects the absorbent liquid pipe 12 and the absorber 2. A liquid bypass pipe, 34 is an on-off valve, 35 is a refrigerant vapor bypass pipe connecting the refrigerant pipe 17 and the absorber 2, and 36 is an on-off valve, which are connected as shown in the figure. Closes when cold water is supplied and opens when hot water is supplied.
[0012]
37 is a frequency converter that converts the electric power applied to the cooling water pump 26 to a desired frequency, 38 is a temperature detecting means that is installed on the evaporator 1 inlet side of the cold / hot water pipe 23 and detects the inflow temperature T1 of the cold water, 39 is a temperature detecting means for detecting the cold water outflow temperature T2 installed on the outlet side of the evaporator 1 of the cold / hot water pipe 23, and 40 is installed on the absorber 2 inlet side of the cooling water pipe 25 for inflow temperature T3 of the cooling water. 41 is a temperature detection means for detecting the temperature T4 of the absorbing liquid installed in the high temperature regenerator 3 and heated in the container.
[0013]
Reference numeral 50 denotes a control device including a microcomputer and the like. A temperature signal is input from the temperature detection means 38 to 41 and the amount of heat input to the high-temperature regenerator 3 and the cooling water flowing through the cooling water pipe 25 are displayed. Control the flow rate.
[0014]
Hereinafter, the configuration of the control device 50 will be described with reference to FIG. 51 is an input means for inputting a detection signal from the temperature detection means 38 to 41, etc., converting the signal and outputting it to the central processing means 52, 53 is a storage means for storing a control program, and 54 is an appropriate control. For example, setting input means for setting the minimum frequency of the power frequency applied to the cooling water pump 26, the changing speed of the power frequency applied to the cooling water pump 26, and the like 55 are used to control the heating power of the gas burner 4. Capacity control output means for receiving a calculation result of the central processing means 52 executed based on the cold water temperature T2 detected by the detection means 39 and outputting a required control signal to the heating amount control valve 22, 56 is an absorber In order to control the number of revolutions of the cooling water pump 26 that supplies the cooling water to the heat exchanger 27 and the condenser heat exchanger 28, the calculation result of the central processing means 52 is received. An external output means for outputting the required control signals to such converter 37.
[0015]
The storage means 53 of the control device 50 converts the high temperature regeneration temperature at the start-up shown in FIG. 3, that is, the temperature T4 of the absorbing liquid heated inside the high temperature regenerator 3 detected by the temperature detection means 41. The relational expression for determining the power frequency applied to the cooling water pump 26 is stored.
[0016]
Then, when the absorption refrigerator is started, the central processing means 52 performs the cooling water pump based on the temperature T4 of the absorption liquid detected by the temperature detection means 41 and the relational expression of FIG. The frequency of the electric power applied to 26 is determined, the frequency of the electric power applied to the cooling water pump 26 is converted into the frequency by the frequency conversion device 37, and the rotation speed of the cooling water pump 26 is controlled.
[0017]
That is, when the absorption chiller is started, the central processing unit 52 causes the cooling water pump 26 to supply the cooling water pump 26 when the temperature T4 of the absorption liquid detected by the temperature detection unit 41 is a predetermined low temperature, for example, 80 ° C. or less. When the cooling water pump 26 is operated at the minimum number of revolutions by applying electric power converted to a predetermined minimum frequency, for example, 30 Hz, and when the temperature detecting means 41 detects a predetermined high temperature, for example, 140 ° C. or higher, the predetermined maximum frequency, For example, when the electric power converted into 60 Hz is applied to the cooling water pump 26 and the cooling water pump 26 is operated at the maximum rotation speed, and the temperature detecting means 41 detects a temperature between a predetermined low temperature and a high temperature, 30 Electric power linearly converted between ˜60 Hz is applied to the cooling water pump 26 so as to linearly control the rotational speed. The control flow at this time is expressed as shown in FIG.
[0018]
Further, in the storage means 53 of the control device 50, a predetermined time, for example, 30 minutes has elapsed since the start of the absorption refrigerator, and the opening degree of the heating amount control valve 22 is a set value for a predetermined time, for example, 5 minutes. For example, when it is 80% or less of the rating, the flow rate ratio with respect to the rating of the cooling water at which the sum of the power fluctuation cost consumed for operating the cooling water pump 26 and the fuel fluctuation cost consumed by the gas burner 4 is minimized. In order to calculate and calculate based on the operating load and the cooling water inflow temperature T3 detected by the temperature detecting means 40, an arithmetic expression determined by a preliminary test or the like is stored, and the cooling water calculated based on the arithmetic expression is stored. In order to obtain this flow rate, the electric power frequency-converted by the frequency converter 37 is applied to the cooling water pump 26 so that the cooling water is subjected to fluctuation control. The control flow at this time is expressed as shown in FIG.
[0019]
Further, when the operation stop signal of the absorption chiller is input, the central processing means 52 calculates the power frequency applied to the cooling water pump 26 when the operation stop signal is input as shown in FIG. The operation of diluting the absorbent is continued for a predetermined time, for example, 10 minutes, in addition to the cooling water pump 26. The control flow at this time is expressed as shown in FIG.
[0020]
In the cold water supply operation by the absorption chiller having the above configuration, the refrigerant evaporated in the high temperature regenerator 3 flows to the condenser 6 through the low temperature regenerator 5 as in the conventional case, and the condenser heat exchanger 28 is cooled by the cooling water pump 26. After cooling and condensing with the cooling water flowing through the refrigerant, it flows to the evaporator 1 via the refrigerant pipe 18. The refrigerant exchanges heat with water flowing through the evaporator heat exchanger 24 to evaporate, and the water flowing through the evaporator heat exchanger 24 is cooled by the heat of vaporization. Then, the cooling water circulates to a load (not shown) to perform a cooling operation or the like.
[0021]
Further, the refrigerant evaporated in the evaporator 1 is absorbed by the absorption liquid in the absorber 2 cooled by the cooling water flowing through the absorber heat exchanger 27 by the cooling water pump 26. The rare absorbing liquid whose concentration is reduced by absorbing the refrigerant is sent to the high temperature regenerator 3 through the low temperature heat exchanger 7 and the high temperature heat exchanger 8 by the operation of the absorption liquid pump 16. The absorption liquid sent to the high temperature regenerator 3 is heated by the burner 4 to evaporate the refrigerant, and the medium concentration absorption liquid flows to the low temperature regeneration 6 through the high temperature heat exchanger 8. In the low temperature regenerator 5, the absorbing liquid is heated by the refrigerant vapor flowing from the high temperature regenerator 8 through the refrigerant pipe 17, and the refrigerant vapor is further separated to increase the concentration. The absorption liquid having a high concentration is lowered in temperature through the low-temperature heat exchanger 7 and sent to the absorber 2 to be dispersed.
[0022]
The cooling water pump 26 of the absorption refrigeration machine is operated at the minimum number of revolutions at the time of startup by the control device 50 of the present invention, and the temperature T4 of the absorbing liquid in the high temperature regenerator 3 detected by the temperature detecting means 41 is detected. Since the rotational speed is increased with the rise, the running cost can be reduced compared with the conventional technique in which the cooling water pump 26 is rated at the start-up when the temperature rise of the absorbing liquid is not sufficient.
[0023]
Further, when a predetermined time has elapsed from the start and the pressure and temperature in the machine are sufficiently stable and the state where the opening amount of the heating amount control valve 22 is small continues for a predetermined time, it is determined that the operating load is small. Since the number of rotations of the cooling water pump 26 is reduced, the running cost can be reduced in this case as compared with the prior art in which the cooling water pump 26 is rated. In addition, it waits until the pressure and temperature in a machine are fully stabilized, and since it determines whether it is a partial load, the determination does not make it mistaken.
[0024]
Further, when the operation of the absorption chiller is stopped, the cooling water pump 26 is continuously operated for a predetermined time at the rotation speed when the operation stop signal is inputted, and the absorption liquid is diluted.
[0025]
For this reason, since the operation load is small, heating by the gas burner 4 is small. Therefore, the concentration of the absorbing liquid is also low, and the absorbing liquid temperature T4 detected by the temperature detecting means 41 is low. When there is no concern that the temperature will be changed, the operation of the pump 26 is based on the low temperature T4 of the absorbing liquid detected by the temperature detecting means 41, or based on the temperatures T1, T2, T3 detected by the temperature detecting means 38, 39, 40. Since the calculated low frequency electric power is applied to the cooling water pump 26 and the cooling water pump 26 is operated at a rotational speed less than the rated value, the cooling water pump 26 is rated for operation and diluted regardless of the concentration and temperature of the absorbing liquid. The running cost can be reduced compared to the conventional technology.
[0026]
In addition, since this invention is not limited to the said embodiment, various deformation | transformation implementation is possible in the range which does not deviate from the meaning as described in a claim.
[0027]
For example, the cooling water pump 26 is operated at the minimum number of revolutions until the start-up control, that is, until the temperature T4 of the absorbing liquid detected by the temperature detecting means 41 detects a low temperature such as a predetermined 80 ° C., Then, instead of the control for increasing the rotational speed of the cooling water pump 26 as the temperature T4 of the absorbing liquid increases, the pressure in the high-temperature regenerator 3 is detected and the rotational speed of the cooling water pump 26 is controlled based on the pressure. Alternatively, the cooling water pump 26 is controlled at a predetermined minimum rotational speed until a predetermined time elapses, and after the predetermined time elapses, the absorption liquid temperature T4 detected by the temperature detecting means 41 or the high temperature regeneration. The rotational speed of the cooling water pump 26 may be controlled based on the pressure in the vessel 3.
[0028]
Moreover, as an absorption refrigerator, it replaces with the gas burner 4 which heats the absorption liquid in the high temperature regenerator 3, and may supply high temperature steam etc. and heat an absorption liquid.
[0029]
Further, the cooling water pump 26 whose operation is controlled by the control device 50 is controlled in the flow rate of the cooling water supplied to the absorber heat exchanger 27 and the condenser heat exchanger 28 by controlling the rotation speed by pole number conversion. It may be a pump to be controlled, or a plurality of pumps are installed in parallel, and the number of units to be operated is controlled to control the flow rate of the cooling water supplied to the absorber heat exchanger 27 and the condenser heat exchanger 28. It may be what you do.
[0030]
Moreover, although the said embodiment demonstrated based on the absorption refrigerating machine of the structure which can supply cold water or warm water, the absorption refrigerating machine which supplies only cold water may be sufficient.
[0031]
【The invention's effect】
As described above, according to the control device of claim 1, the cooling water pump is operated at the minimum number of revolutions when the absorption chiller is started up, and the number of revolutions is increased as the temperature of the absorbent in the high-temperature regenerator rises. Therefore, the running cost can be reduced as compared with the conventional technique in which the cooling water pump is rated from the start-up when the temperature rise of the absorbing liquid is not sufficient.
[0032]
Further, according to this control device, when the operating load is small, the number of rotations of the cooling water pump is reduced, so that in this case as well, the running cost can be reduced compared to the conventional technique in which the cooling water pump is rated regardless of the operating load. .
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a configuration example of a control device of the present invention.
FIG. 2 is an explanatory diagram showing a configuration of an absorption refrigerator controlled by the control device of the present invention.
FIG. 3 is an explanatory diagram showing a power frequency applied to the cooling water pump when starting the absorption refrigerator.
FIG. 4 is an explanatory diagram showing a control flow.
FIG. 5 is an explanatory diagram showing a control flow.
FIG. 6 is an explanatory diagram showing the power frequency applied to the cooling water pump when stopping the absorption refrigerator.
FIG. 7 is an explanatory diagram showing a control flow.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Evaporator 2 Absorber 3 High temperature regenerator 4 Gas burner 5 Low temperature regenerator 6 Condenser 7 Low temperature heat exchanger 8 High temperature heat exchanger 11/12/13/14/15 Absorbing liquid piping 16 Absorbing liquid pump 17/18/19 Refrigerant pipe 20 Refrigerant pump 21 Gas pipe 22 Heating amount control valve 23 Cold / hot water pipe 24 Evaporator heat exchanger 25 Cooling water pipe 26 Cooling water pump 27 Absorber heat exchanger 28 Condenser heat exchanger 29 Refrigerant bypass pipe 30 Refrigerant liquid Reservoir 31 Absorbing liquid reservoir 32 Open / close valve 33 Absorbing liquid bypass pipe 34 Open / close valve 35 Refrigerant vapor bypass pipe 36 Open / close valve 37 Frequency converter 38/39/40/41 Temperature detecting means 50 Control device 51 Input means 52 Central processing means 53 Storage means 54 Setting input means 55 Capacity control output means 56 External output means

Claims

In an absorption chiller control device having a function of outputting a control signal for controlling the amount of heat supplied to the high-temperature regenerator and a control signal for controlling a cooling water pump for supplying cooling water to the absorber and the condenser, A control signal for supplying a constant amount of cooling water less than the rated value is supplied until a predetermined time has elapsed from the start of the absorption refrigerator or until the temperature or pressure in the high-temperature regenerator rises to a predetermined value. Output to the pump and either a predetermined time has elapsed since the start of the absorption refrigerator or the temperature or pressure in the high temperature regenerator rises to a predetermined value and is supplied to the high temperature regenerator When the amount of heat to be generated is equal to or less than a set value for another predetermined time shorter than the predetermined time, the power fluctuation cost for operating the cooling water pump and the fuel fluctuation of the heat amount supplied to the high temperature regenerator A control signal for variably controlling the flow rate of the cooling water so as to obtain a cooling water flow rate calculated based on a predetermined arithmetic expression for calculating a flow rate ratio with respect to the cooling water rating at which the sum of A control device for an absorption refrigeration machine, characterized in that it is output to a cooling water pump .