Details and Descriptions
Graphic and Image descriptions
Fig. A1 Psychrometric Process for Computer Room A/C Units with Dry Coil Operation, Appendix A, Section A3.1
Figure A1 depicts dry coil operation. Air enters the cooling coil at condition R and leaves the coil at condition C. It mixes with bypass air at condition R to form a mixture at condition M. There is a temperature rise of 1.5 °C between the coil and the entry into the room, hence it enters the room at condition S. All of these processes occur at constant sensible heat ratio of 1.0, therefore the psychometric process follows a horizontal line R-S-M-C.
Fig. A2 Psychrometric Process for Computer Room A/C Unit with Wet Coil Operation, Appendix A, Section A3.1
Figure A2 describes the processes that occur if there is wet coil operation - i.e. if condensation occurs at the coil. Since there is condensation, the psychometric process no longer follows a horizontal line, and the air leaves the coil at condition C1. There is a change in enthalpy between conditions C and C1, depicted as LHc in Figure A2. Air is now supplied at condition S1, and it has to return to condition R during the cooling process. Hence, the psychometric process follows the horizontal line (at constant SHF), and then an enthalpy change is required to return to condition R from R1. This is shown as LHh. Thus, it is seen that two enthalpy changes are required, LHc and LHh, so there is, in effect, a double penalty on the cooling system.
Fig. A3 Chilled Water or Glycol-cooled Computer Room A/C Units, Appendix A, Section A.4.3
Figure A3 shows one possible arrangement, with a heat recovery device. The dry cooler heat exchanger is provided for free cooling and energy conservation. The cooling coil controls should include 3-way valves (an air cool chiller unit, a filling funnel and a dry cooler heat exchanger) to ensure adequate flow through the chiller at all times. This system is used when the distances between condenser and compressor are too great for the use of refrigerant cooled unit. It is a relatively maintenance free system.
Fig. A4 Heat Recovery System for use with Glycol-cooled Condensers, Appendix A Section A5.0
Figure A4 shows how the domestic water heater and the condenser are arrange to recover the heat for heating domestic water. When T-1 calls for heat, glycol is drawn through the heat recovery loops, circulating pump P-1. The flow varies through the modulating Valve V-1 bypass.
Fig. A5 Energy Conservation – Additional Cooling Coil to Utilize Condenser Fluid, Appendix A, Section A 5.4
Figure A5 shows how to divert the condenser fluid from the refrigerant condenser to an additional cooling coil in the A/C unit. The fluid is emptied in the filling funnel which leads to an expansion tank, which is cooled down by the dry cooler heat exchanger. The glycol condenser pump is activated and enables V-1 to activate energy conservation with additional cooling coil to utilize condenser fluid.
Typical Telecom System
This image illustrates the typical telecommunication infrastructure in a building, with at least one telecommunication room at each floor, serving up to 1000 m2 of floor space and each is dedicated to telecommunication function. Each floor contains at least one telecommunications room (TR) ranging in size, depending on the floor area served. Each TR may serve up to 1000 square metres (10,000 square feet) of floor space and each is dedicated to the telecommunications function. Horizontal pathways carry telecommunications cables from the TR to the vicinity of the work area being served.
Typical Zoned Conduit Horizontal Pathway
This image illustrates a zone distribution system based on a conduit. Horizontal pathways carry telecommunications cables from the TR to the vicinity of the work area being served. Horizontal pathways support a zone-distribution system where the zone is the area between four column. The Equipment Room is the central point for telecommunications within the building. When sized according to standards, the Equipment Room will be quite large and should have ample space to house LAN servers as well. The Equipment Room is typically located in the basement, but it need not be. It may also function as a TR serving work areas located on its floor.
Typical Telecom Cabling System
This image illustrates the typical telecommunications-cabling infrastructure in a building. Horizontal cabling consists of two (or more) cables (typically one for voice and one for data) that are run to each work area from a telecommunications room (TR) located on the same floor as the work area. This is called "star wiring" with the TR being analogous to the centre of the star and each work area being analogous to the points of the star. Each cable is terminated on a jack at the work area and on a cross-connection field in the TR.
Multi-department Building: Legacy Approach
This image illustrates the telecommunications infrastructure in a typical building house multiple departments designed from the perspective of individual departments. Each department creates its own main cross-connect (M.C.) in a telecommunications room on one of the floors it occupies, so this room functions like an equipment room (ER) for that department. As illustrated, it may be enlarged to accommodate additional equipment. Each department installs backbone pathways and backbone cables connecting each telecom room on each floor it occupies to the department's main cross-connect. Each department also establishes a point of demarcation (demarc.) with the facilities of the telecom carriers on a floor it occupies – typically adjacent to the department's main cross-connect. In this illustration, "X" represents a cross-connection.
Typical Zoned Conduit Horizontal Pathway (Holistic Approach to Telecommunications Infrastructure)
This image illustrates a system of cable trays or conduits that radiates from each telecom room to the work areas being served. Typical factors driving this approach are tradition, security concerns about sharing space with another department, and a department simply exerting its "sphere of influence".
Multi-department Building: Holistic Approach
This image illustrates the holistic telecommunications infrastructure in a multi-department building. All points of demarcation are located in the Entrance Room/CER. A single Main Cross-Connect (M.C.) is established in the Equipment Room. All backbone cables are run from the main cross-connect to cross-connections located in a telecom room (or rooms) located on each floor.
Typical Telecom System (Telecommunications Infrastructure in Buildings)
This image illustrates the typical telecommunications infrastructure in a building. Each floor contains at least 1 telecommunications room (TR). Each TR serves up to 10,000 square feet of floor space and each is dedicated to the telecommunications function. Two (or more) cables are run to each work area from a TR located on the same floor as the work area. Each cable is terminated on a jack at the work area and on a cross-connection field in the TR.
Multi-tenant Building: Legacy Approach
This image illustrates telecommunications infrastructure in a typical building housing multiple departments. Each department creates its own main cross-connect on one of the floors it occupies. Each department installs pathways and backbone cables connecting each of the floor telecom room to the department's main cross-connect. And each department establishes a point of demarcation with the facilities of the telecom carriers at a location on a floor it occupies adjacent to the department's main cross-connect.
Multi-tenant Building: Holistic Approach
This image illustrates the holistic telecommunications infrastructure in a building housing multiple departments. This holistic system readily adapts to changes in space allocations between tenants or the addition of new tenants. It accommodates fluctuations between single and multiple occupancy of the building. It readily permits tenants to select their telecommunications common carriers and change them as required. It provides a system of telecom rooms and pathways that should endure until the building requires major renovations.
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