Abstract:
La présente invention concerne un procédé pour maintenir la qualité du manteau neigeux (3) couvrant la surface d’une piste (2) d’une installation couverte de ski ou autre sport de glisse, laquelle installation comprend - un hall (1) isolé thermiquement recouvrant ladite piste (2), - des moyens de production de neige (4), et - des moyens (5) de régulation de la température de l’air ambiant au sein dudit hall (1). Le procédé conforme à l’invention consiste à faire varier la température de l’air ambiant du hall (1) selon des cycles réguliers ou sensiblement réguliers, par le contrôle des moyens de régulation de la température (5), entre : - une première température T1 (de préférence légèrement positive comprise entre 1 et 5° C), adaptée pour faire subir une fonte partielle superficielle au manteau neigeux (3), laquelle température T1 est maintenue pendant un temps t1 inférieur au temps nécessaire à la fonte totale du manteau neigeux (3), et - une seconde température T2 (de préférence négative, comprise entre -10 et -2° C), adaptée pour la fabrication de la neige par la mise en oeuvre des moyens de production correspondants (4), laquelle température T2 est maintenue par un temps t2 durant lequel une quantité suffisante de neige est fabriquée pour renouveler celle fondue par le temps t1 . La période des cycles de température est avantageusement de l’ordre de 24 heures.
Abstract:
Falling film and hybrid falling film evaporators are provided for use in a two-phase refrigeration system or process system. The evaporator includes a shell having an upper portion, a lower portion, and a tube bundle having tubes extending substantially horizontally in the shell. A hood disposed over the tube bundle has an upper end adjacent the upper portion above the tube bundle, the upper end having opposed substantially parallel walls extending toward the lower portion, the walls terminating at an open end opposite the upper end. Once liquid refrigerant or liquid refrigerant and vapor refrigerant is deposited onto the tube bundle, the substantially parallel walls of the hood substantially prevent cross flow of refrigerant vapor or liquid and vapor between the tubes of the tube bundle. A flow distributor disposed adjacent the open end between the hood and the shell modifies the refrigerant flow, providing more uniform refrigerant flow distribution.
Abstract:
A refrigerant circuit using a vapor compression cycle, the circuit usable for air conditioning, refrigeration or heat pump purposes. The circuit includes a lubricated compressor connected to an oil separator vessel separate from the compressor, a falling film or hybrid falling film evaporator and a condenser. The oil separator vessel extends substantially horizontally. The oil separator vessel is separated into a primary space and a secondary space by a filter pad configured to substantially remove entrained oil droplets of about 5 µm and larger from the refrigerant entering the oil separator vessel. The primary space is in fluid connection with a discharge of the compressor. The secondary space is in fluid connection with an inlet of the condenser. The circuit has an oil entrainment flow discharge of lubricant from the compressor of at least about two percent by mass relative to refrigerant flow.
Abstract:
An evaporator (168) in a vapor compression system (14) (168) includes a shell (76), a first tube bundle (78); a hood (86); a distributor (80); a first supply line (142); a second supply line (144); a valve (122) positioned in the second supply line (144); and a sensor (150). The distributor (80) is positioned above the first tube bundle (78). The hood (88) covers the first tube bundle (78). The first supply line (142) is connected to the distributor (80) and an end of the second supply line (144) is positioned near the hood (88). The sensor (150) is configured and positioned to sense a level of liquid refrigerant (82) in the shell. The valve (122) regulates flow in the second supply line in response to the level of liquid refrigerant (82) from the sensor (150).
Abstract:
A cooling system provided for a motor powering a compressor in a vapor compression system. The cooling system includes a housing enclosing the motor and a cavity located within the housing. A fluid circuit has a first connection with the housing configured to provide a liquid or two phase cooling fluid to the motor. The two phase cooling fluid is separable into a vapor phase portion and a liquid phase portion. The fluid circuit further has a second connection with the housing to remove cooling fluid in fluid communication with the fluid circuit. The cooling fluid conveyed through the second connection is two phase cooling fluid. The fluid circuit further has a third connection with the housing for receiving and circulating in the cavity the vapor phase portion conveyed through the second connection.
Abstract:
A vapor compression system including a heat exchanger and a heat exchanger for use in a vapor compression system, the heat exchanger including a shell (76), a hood (86), a tube bundle (78), a distributor (80), and a passageway are disclosed. The shell (76) can include an outlet (104) configured to permit passage of vapor (96) from the shell (76), the hood (86) can be configured and positioned to cover the tube bundle (78) and the distributor (80), the tube bundle (78) can extend substantially horizontally in the shell (76), the distributor (80) can be configured to apply a fluid to the tube bundle (78), and the passageway can be configured and positioned to receive vapor (96) and provide a flow path for the vapor (96) to the outlet (104).
Abstract:
A falling film evaporator is provided for use in a two-phase refrigeration system or process system. The evaporator (80, 280) includes a shell (100) having an upper portion (102), a lower portion (104), and a tube bundle (106) having tubes extending substantially horizontally in the shell (100). A hood (112) is disposed over the tube bundle (106), the hood (112) having an upper end (114) adjacent the upper portion (102) above the tube bundle (106), the upper end (114) having opposed substantially parallel walls (116) extending toward the lower portion (104), the walls terminating at an open end (118) opposite the upper end (114). Once liquid refrigerant (120) or liquid refrigerant (120) and vapor refrigerant is deposited onto the tube bundle (106), the substantially parallel walls (116) of the hood (112) substantially prevent cross flow of refrigerant vapor or liquid and vapor between the tubes of the tube bundle (106).
Abstract:
A generator system is operated at variable speeds to provide power to a plurality of motors. The motors are connected to the generator system through a common electrical bus and a disconnect device. The motors each drive a compressor in a chiller system. The chiller system includes a speed and control algorithm, and a data collection network to obtain operating parameters from the associated chiller system. A control system determines a number of compressors to operate and manages the loads of the chiller systems, and determines an operating frequency of the generator required to obtain an operating speed of the motors to maintain a desired temperature of the chiller system.
Abstract:
A system and method for controlling compressor capacity while maintaining compressor stability includes providing a compressor and a flow reduction device for controlling flow of refrigerant through the compressor; measuring suction pressure and discharge pressure of the compressor; calculating a compressor head factor based on the suction discharge pressures; calculating the speed of sound in the refrigerant; calculating the tip speed of the impeller divided by the speed of sound; calculating the tip speed of the impeller at the minimum Mach number; calculating a multiplier of speed increase as a function of the flow reduction device based on an actuator feed-back signal; determining a minimum rotational speed at which the compressor may operate free from a surge condition; and controlling a rotational speed of the compressor above the minimum rotational speed.
Abstract:
A distributor for use in a vapor compression system including an enclosure configured to be positioned in a heat exchanger having a tube bundle comprising a plurality of tubes extending substantially horizontally in the heat exchanger. A plurality of distribution devices are formed in the enclosure, the plurality of distribution devices configured to apply a fluid entering the distributor onto the tube bundle. The enclosure is formed of unitary construction.