SERVICES ASSIGNMNENT TASK A by

HVAC systems. What are they?

k002500791 — 2023-10-17 19:44:15 UTC

HVAC stands for Heating Ventilation and Air Conditioning.

Benefits of implementing HVAC systems into building development

k002500791 — 2023-10-17 19:49:37 UTC

1) Save money in utilities
2) Improved Air humidity and health benefits
3) Limits exposure to extreme temperatures
4) Better air quality
5) Less airborne pollutants

k002500791 — 2023-10-17 21:23:59 UTC

k002500791 — 2023-10-17 21:24:10 UTC

k002500791 — 2023-10-17 21:26:38 UTC

k002500791 — 2023-10-17 21:29:45 UTC

Equipment rooms: since the total mechanical and electrical space requirements range between 4 and 9% of the gross building area. It is preferable to be centrally located in the building to reduce the long duct, pipe, and conduit runs and sizes, to simplify shaft layouts, and centralized maintenance and operation.
HVAC Facilities: The design of equipment rooms to host both pieces of equipment should consider the size and the weight of equipment, the installation and maintenance of equipment, and the applicable regulations to combustion air and ventilation air criteria.
Vertical shaft: provide space for air distribution and water and steam pipe distribution. The air distribution contains HVAC supply air, exhaust air, and return air ductwork. Pipe distribution includes hot water, chilled water, condenser water, and steam supply, and condenser return. The vertical shaft includes other mechanical and electrical distribution to serve the entire building including plumbing pipes, fire protection pipes, and electric conduits/closets.
Equipment access: the equipment room must allow the movement of large, heavy equipment during the installation, replacement, and maintenance.

Reference 3)

k002500791 — 2023-10-17 21:30:07 UTC

1) ASHRAE Handbook. HVAC Systems and Equipment. Atlanta, GA: American Society of Heating, Refrigerating, and Air Conditioning Engineers; 1996. pp. 1-10

2) American Society of Heating, Refrigerating & Air-Conditioning Engineers. ASHRAE Handbook. Fundamentals: SI ed. Amer Society of Heating, Atlanta, GA; 2009

3) Haines RW, Myers ME. HVAC Systems Design Handbook. McGraw-Hill Education; 2010

4) ASHRAE Handbook. Fundamentals. Atlanta: American Society of Heating, Refrigerating and Air Conditioning Engineers; 2001. p. 111

k002500791 — 2023-10-18 10:12:18 UTC

A single zone system consists of an air handling unit, a heat source and cooling source, distribution ductwork, and appropriate delivery devices. The air handling units can be wholly integrated where heat and cooling sources are available or separate where heat and cooling source are detached.

Reference 4)

k002500791 — 2023-10-18 10:15:18 UTC

The dual duct all-air system is a terminal-controlled modification of the multi-zone concept. A central air handling unit provides two conditioned air streams such as a cold deck and a hot deck

Reference 4)

k002500791 — 2023-10-18 10:17:44 UTC

Some spaces require different airflow of supply air due to the changes in thermal loads. Therefore, a variable-air-volume (VAV) all-air system is the suitable solution for achieving thermal comfort.

The VAV system consists of a central air handling unit which provides supply air to the VAV terminal control box that located in each zone to adjust the supply air volume

Reference 4)

k002500791 — 2023-10-18 10:21:26 UTC

The fan-coil unit can be placed in the room or exposed to occupants, so it is essential to have appropriate finishes and styling. For central systems, the fan-coil units are connected to boilers to produce heating and to water chillers to produce cooling to the conditioned space. The desired temperature of a zone is detected by a thermostat which controls the water flow to the fan-coil units.

Reference 4)

k002500791 — 2023-11-07 12:45:55 UTC

Regulating dampers direct the air flow to either the heating or the cooling exchanger coil.

k002500791 — 2023-11-07 12:48:16 UTC

Chilled water is produced via a centralised plant and then circulated to services throughout the building.

k002500791 — 2023-11-07 12:52:39 UTC

These systems deliver a constant volume of conditioned air from the AHU. They are not suited to multi-zoned buildings with varying cooling requirements, therefore they are generally used in single zones, such as a central foyer or as part of a cooling system with the primary cooling being achieved by other means, such as FCUs.

k002500791 — 2023-11-07 12:55:48 UTC

Active chilled beams operate in the same principle as the passive with the exception of having fresh air ducted to it. Rather than air being drawn into the beam by buoyancy it is induced by the ducted air.

k002500791 — 2023-11-07 12:57:59 UTC

A cooling tower is more efficient than a dry air cooler because it uses evaporated water to assist the rejection of unwanted heat but requires greater maintenance.

k002500791 — 2023-11-07 13:05:48 UTC

Warm water is piped across fans within the dry air coolers forcing the temperature of the water to drop.

k002500791 — 2023-11-07 13:07:02 UTC

Long rectangular units located at high level circulate chilled water in finned pipes and exchange coolth. Convection occurs with warm rising air being cooled by the chilled beams.

k002500791 — 2023-11-07 13:07:40 UTC

A fan blows air across a heat exchanger coil that will contain hot or cold water (or refrigerant for VRF/VRV systems).

k002500791 — 2023-11-07 13:08:19 UTC

AHUs maintain adequate ventilation by providing fresh, filtered outside air and delivering it at the condition required to the internal space. AHUs can be used to control the temperature and humidity of the air.

k002500791 — 2023-11-07 13:09:17 UTC

The system is split into an outdoor heat rejection unit and an indoor room cooling unit. The refrigerant is pumped directly between the units and operates with 2-pipe connections.

k002500791 — 2023-11-07 13:10:35 UTC

Variable Refrigerant Flow (VRF) and Variable Refrigeration Volume (VRV) systems circulate refrigerant like a split system but have multiple indoor units providing simultaneous heating and cooling. They can operate with a 2- or 3-pipe connection.

k002500791 — 2023-11-07 13:11:02 UTC

FCUs that use refrigerant will often have 3-pipe connections (hot and cold flow and a single return) allowing for simultaneous heating and cooling to separate zones. Some systems achieve simultaneous heating and cooling with only 2-pipes (flow and return) where the flow pipe contains refrigerant in both vapour (for heating) and liquid (for cooling) form.

k002500791 — 2023-11-07 13:11:27 UTC

2-pipe FCUs have only one coil so they can only provide heating or cooling at any one time. Their mode can be changed on a seasonal basis as required.

k002500791 — 2023-11-07 13:11:54 UTC

4-pipe FCUs have dedicated coils for heating and cooling and thus four pipe connections (hot and cold flow and returns).

k002500791 — 2023-11-07 13:12:50 UTC

Plant equipment to produce chilled water. Heat is removed from an unwanted area and rejected externally. Packaged chillers include heat rejection as part of the unit. Other chillers require dedicated heat rejection plants, such as dry air coolers and cooling towers.

k002500791 — 2023-11-07 13:20:37 UTC

Air is supplied from the AHU at a constant temperature to a number of VAV units, each with a damper which controls the flow of air through it depending on the cooling or heating loads.

Case Study : Kilmatec (2021)

k002500791 — 2023-11-07 15:22:35 UTC

Installed chiller onto an existing chilled water system supplying pressure test rigs

https://www.klimatec.co.uk/case-study-4

Limitations

k002500791 — 2023-11-07 15:25:25 UTC

High requirements for water quality
High Maintenance costs
Large weight index

Case Study (Fujitsu Ductless HVAC Installation Portsmouth, NH)

k002500791 — 2023-11-07 15:40:13 UTC

Problem: The Dinsmore family wasn’t satisfied with the heating and air conditioning solution for the second floor of their home. They decided it was time to fix this problem once and for all before the next summer rolled around.

Solution: The homeowner contacted Townsend Energy and asked for a consultation. We sent our HVAC specialist Mike Mondalto to the property to consult with the owners while assessing the situation. He recommended installing a Fujitsu ductless mini-split system.

https://www.townsendtotalenergy.com/case-studies/ductless-installation-portsmouth-nh

Limitations

k002500791 — 2023-11-07 15:46:16 UTC

Require sufficient wall space (space limitations)
Require regular maintenance
Installation cost (professional installation & cost of split system asset)

https://www.linkedin.com/pulse/pros-cons-split-ac-cool-comfort-chilling/

Case study

k002500791 — 2023-11-07 15:52:42 UTC

A 60,000-sq-ft government administration building constructed during the mid-1950s, comprised of a basement and four floors, had two constant volume multi-zone dual-duct (MZ-DD) air handling units (AHUs) to provide both cooling and heating. The AHUs were located in separate mechanical rooms, one in the basement while the other was on the top floor. (Schrecengost, R,. 2019)

https://www.csemag.com/articles/case-study-flexible-reliable-hvac-system/

Limitations

k002500791 — 2023-11-07 16:04:38 UTC

supply air temperature is varied, but, the volume flow rate (supply) of air is constant.

https://theengineeringmindset.com/constant-air-volume-cav/

Case Study (GTI Energy 2019)

k002500791 — 2023-11-07 16:11:40 UTC

GTI conducted a side-by-side demonstration of two VRF heat pump technologies that offer significant potential for energy and cost savings, as well as improved comfort with zoned temperature control.