What's New in HVAC

Basic Load Calculations: 

• Cobeal establishes summer/winter design weather conditions paying particularly close attention to regional weather issues and impact on humidification/dehumidification considerations. 
• All elements of the building envelope are identified so that thermal energy loss/gain can be determined. Reference to ASHRAE Standard 901.2 for regionally documented envelope construction minimal thermal quality considerations, include: 
  • Orientation of walls and roofs are defined so that sun angle impacts can be evaluated. 
  • The composite construction of all walls, roofs, and floors are defined so that thermal transfer calculations can be performed. This information is also useful when a dew point analysis is performed on the envelope. 
  • Thermal mass and color of walls and roofs are defined so that thermal time lags and radiation absorption can be evaluated. 
  • Fenestration U-valves and solar heat gain coefficients are defined. 
  • External/internal shading provisions that may impact fenestration heat gain are defined. 
• Lighting
  • Cobeal maps lighting densities and ballast loss factors per individual space. Maximum densities are identified for individual space types in ASHRAE 90.1. 
  • Cobeal looks for opportunities to capture natural light (daylighting) and apply occupancy sensing techniques to reduce light heat gain. 
• Basic internal sensible heat gain allowances are made for receptacle loads. 
• Miscellaneous sensible and latent heat gain values are identified for special circumstances. 
• People contributions: 
  • Cobeal calculates into HVAC&R designs the total number of people and the occupancy usage profiles.
  • The activity levels of people are also identified. 
• Ventilation
  • For a given space, Cobeal calculates per ASHRAE Standard 62.1 the area factor and people factor ventilation rate components. 
  • Depending on HVAC system architecture employed, Cobeal's critical space calculations are performed to adjust ventilation quantities to ensure adequate outside air is being provided to occupied spaces during all system fluctuations. 
  • Cobeal calculates all building exhaust requirements and compares this to minimum required outside air ventilation rates. The overall impact of building pressurization dynamics are evaluated for the facility, for seasonal conditions, and for regional locations. Cobeal fully understands how moisture and thermal gradients work with the building envelope construction and what influence infiltration/exfiltration has on condensation potential. 
• Basic System Zoning  
  • Spaces and zones are identified. 
  • Summer/winter design temperature set-point conditions and dead-band ranges per thermal comfort recommendations of ASHRAE Standard 55 are established. 

Energy Modeling

• Cobeal establishes realistic average weather profiles for project location. 
• Cobeal defines realistic 24-hour usage profiles for the entire calendar year taking into account workdays, weekends, holidays, etc. 
• Cobeal obtains current rate structures from utilities. 
• Cobeal accurately defines maintenance costs for equipment and system alternatives. 

Moisture Control

• Cobeal mitigates water generation sources inside the facility. 
• Cobeal properly applies to the climate zone the relationship of vapor retarders and air barriers needed in the construction of the building envelope. 
• All possible relative building air pressure relationships (internal and external) are considered to avoid brining undesirable, untreated moisture into the facility.  

Ventilation and Dedicated Outside Air Systems (DOAS)

• Cobeal addresses the difficult design challenges of ASHRAE Standard 62.1 by performing calculations to measure the correct amount of air ventilation for a given space/zone/facility layout.
• When multiple spaces are included into the same zone, Cobeal calculates the correct ventilation rate that ensures adequate distribution to all spaces and zones for all operating conditions. Depending on the zoning configuration, multiple space calculations may need to be made to increase the minimum required outside air quantity. 
• The utilization of excessive outside air has a significant impact on cooling/heating loads and the sizing/selection of equipment and plant solutions. Additionally, high quantities of moisture can enter a building. As latent cooling requirements increase, sensible heat ratios decrease. As sensible heat ratios drop, the proper application of equipment to maintain space temperature and humidity becomes more complex. 
• Increase outside air quantities also impact the minimum setting on variable volume terminal units. 
• Cobeal provides creative solutions to address multiple issues. For example: 
  • Cobeal may call for a DOAS approach to allow the outside air latent load to be decoupled from the space sensible load. The outside air path is conditioned based on dew point to deliver neutral or cold air to a parallel space sensible cooling system. Space temperature is then independently controlled by the sensible cooling system. 
  • Cobeal can deliver a 100% outside air, not mixed, at the prescribed quantity directly to the space based on the people and area factor ventilation rates.
  • Since no mixing is involved, ventilation rate delivery to the space/zone can be verified and continuously monitored. 
  • ASHRAE Standard 62.1 requires occupied spaces be held below 65% relative humidity. The above approach now makes achievable a part-load cooling condition. 
  • Problems with scroll compressor units cycling off when leaving air temperature is resolved and raw outside air is pulled across a de-active coil. The phenomena of moisture on the coil and in the drain pan being re-evaporated back into the unconditioned air path is now eliminated. 

Ozone Depletion

• Refrigerants are the fundamental substances used to transfer heat during the mechanical cooling process. Chloroflurocarbon (CFC) compounds such as R-11 and R-12 have been used for decades in refrigeration cycles. These same refrigerants are used as blowing agents in the manufacturing of foams and insulations. 
• Evidence has linked the reduction of strateospheric ozone concentrations to the release of halogenated refrigerant vapor into the atmosphere. As refrigerant concentrations are hit by the sun's ultraviolet light, the refrigerant molecules break down and release chlorine atoms into the atmosphere. Once liberated, the chlorine atoms react with very cold polar stratospheric clouds containing water vapor and nitric acid to destroy the ozone concentration. As the ozone layer is depleted, the sun's ultraviolet radiation (UV-B) becomes less filtered and reaches the earth's surface at higher concentrations. 
• Fortunately, CFC refrigerants have been replaced with hydrochloroflourocarbons (HCFC) and hydroflourocarbons (HFC) alternatives. Natural refrigerants, such as ammonia and carbon dioxide, which are not ozone depleting substances, are seeing use in certain applications. 
• Cobeal understands the current phase-out timetables set by the Montreal Protocol (adopted in 1987) and subsequent amendments, the science of the available alternatives, the impacts to system design, and the impact on performance and energy efficiency. 
  • In renovation projects, Cobeal has encountered HVAC systems with out-of-production CFC refrigerants. Removal, cleaning, and disposal / reclaim of the refrigerant is followed using strict EPA guides to prevent release of the refrigerant to the atmosphere. 
  • Cobeal follows ASHRAE Standard 147 to reduce the release of halogenated refrigerants from refrigerating and air-conditioning equipment and systems. 
  • Cobeal considers the dynamics of phase-out systems in relation to the over-all life of the facility and the total ownership cost impact. 
  • Cobeal considers critical toxicity and flammability issues, as well as equipment room locations and safety design. 
  • The thermodynamic characteristics of alternatives can result in less efficient cooling processes. Cobeal balances the correct amount of ozone depletion potential of the refrigerant being used in relation to the global warming potential of energy inefficiency and the release of carbon dioxide into the atmosphere. 

Some critical environments are faced with complex thermal issues. These high performance HVAC&R solutions must be integrated and coordinated with parallel design and planning activities. The following discipline considerations are considered: 

Architectural Interaction

• IMPACTS BY
  • Equipment room locations, accessibility, and size
  • Location and appearance of air distribution devices
  • Floor to floor height, depth of structure, ceiling height, and available utility space in ceiling cavity
  • Component aggregation and location of building envelope elements 
  • Location of Life Safety features such as fire and smoke rated construction and the impacts of HVAC constructability
  • Location and construction of noise sensitive areas
  • Selection of interior finishes and VOC impacts
• IMPACTS TO
  • Location of equipment
  • Orientation of the building 

Structural Engineering Interaction

• IMPACTS BY
  • Type of construction: steel, concrete, wood, etc. 
  • Foundation design
  • Fireproofing techniques
  • Seismic criteria
• IMPACTS TO
  • Location, weights, and support/attachment of equipment

Civil Engineering Interaction

• IMPACTS BY
  • Location of site utilities
  • Sitting and landscaping impacts on thermal loads and noise trespass
• IMPACTS TO
  • Size and location of utility connections

Electrical Engineering Interaction

• IMPACTS BY
  • Size of available power service
  • Layout of design
  • Gen-set ventilation, heat removal, and fuel support requirements 
  • Location of electrical infrastructure: switchboards, panels, feeders, etc. 
• IMPACTS TO
  • Equipment power requirements
  • Coordination of power hook-up and disconnecting means
  • Coordination of Fire Alarm shut-down and smoke detectors
  • Location of duct, pipe, and air distribution

Plumbing Engineering Interaction

• IMPACTS BY
  • Type and capacity of heat generation plant for hot water heating
  • Location of plumbing infrastructure: equipment, piping, etc. 
• IMPACTS TO
  • Make-up water requirements and backflow protection
  • Condensate drainage disposal requirements
  • Location of duct, pipe, and air distribution

Fire Protection Engineering Interaction

• IMPACTS BY
  • Fire pump ventilation, heat removal, and fuel support requirements
  • Location of sprinkler and standpipe infrastructure: equipment, piping, heads, etc. 
• IMPACTS TO
  • Location of duct, pipe, and air distribution

Acoustics Engineering Interaction

• The fundamentals of equipment sound power levels, transmission paths, and resulting sound pressure readings go beyond the application and understanding of basic thermodynamics. 
• Cobeal has sufficient understanding of acoustics to be able to benchmark the sound quality of the equipment applied as the design solution and attenuate sound paths accordingly to the acoustical criteria for occupied spaces. 
• The issuance of ANSI 12.60-2002 changed the integrated design dynamic. Successful compliance with this standard requires a concentrated coordination effort between Cobeal's mechanical engineers and general construction interests. 
• All sound transmission paths (discharge, radiated, breakout, etc.) are analyzed to show anticipated space sound pressure based on equipment selection sound power source energy. 
• Equipment locations, equipment operating points, transmission path construction, end room reflectance, and resulting sound pressure variables are verified and communicated to the entire team. 

High Density Data Server Integration

• Facilities are becoming "smarter" and fully networked. This high-tech trend has created a new challenge for the mechanical engineer of record (MER). 
• Communication and data storage servers are adding significant sensible cooling loads to the indoor environment. As server technology improves to provide faster speed and larger capacity, the sensible heat rejection load component keeps rising. 
• Heat rejection densities for server equipment are doubling and, in some cases, tripling. 
• High density loads, hot/cold aisles, and phased capacity methodology are new issues that Cobeal addresses. 

Indoor Environmental Quality (IEQ) Engineering Integration

• Cobeal's holistic, integrated response goes beyond HVAC&R expertise, considering occupant comfort and building related illnesses. Temperature, humidity, drafts, indoor pollutants, biological agents, and non-biological particles and fibers are considered. 
• Cobeal IEQ engineers know how to prevent building related illnesses, including: hypersensitivity, pneumonitis, and Legionnaire's disease; as well as common health complaints, like: eye/nose/throat irritation, headaches, fatigue and lethargy, upper respiratory symptoms, and skin irritation or rashes.
• Cobeal is cognizant of the following issues and works with clients to address them right away: 
  • Volatile Organic Compounds (VOC) pose a source challenge based on the variety of source opportunities and possible chemical introductions to the building. Sources can include: construction materials, furnishings, cleaning products, copiers/printers, environmental tobacco smoke, people, personal hygiene products, air fresheners, and outdoor air. Cobeal considers which elements should be eliminated, substituted, or contained. 
  • Cobeal achieves effective temperature and humidity control with the application of appropriate systems, effective air distribution, and proper control sequences. Humidity levels can negatively impact mucous membranes and upper respiratory tracts. Cobeal considers high humidity levels and their support of mold growth and bacteria. 
  • Cobeal designs air systems that factor in the possible spread of airborne infectious agents, such as viruses and bacteria, generated by the occupants inside the building. As part of Cobeal's risk management analysis, infrastructure solutions such as the extent of filtration, UV light treatment, ventilation effectiveness, air changes, and building pressure control are investigated. 
  • The building or systems within it may be sources of infectious agents such as fungus or bacteria. These sources can contribute to significant invasive diseases such as aspergillosis, legionellosis, and histoplasmososis. Cobeal minimizes the introduction of moisture into the building and ventilation system, which is critical to the mitigation of these fatal diseases. 
  • The growth and support of non-infectious biological agents (fungus, bacteria, dander, and allergens) is minimized. Cobeal optimizes with site dynamics the locations of outside air ducts. Sources of moisture generation and intrusion are eliminated. Cobeal's solutions maintain filtration and proper operation of critical equipment. 
  • Cobeal considers non-biological particles. Sources include the quality of the outside air available, tobacco smoke generation, combustion products, process related dust / fume generation, and material generated particles. Construction activities are also a significant source of fine and large particles. Early occupancy of new construction can present a liability to the owner. 
  • Inorganic gases such as carbon monoxide, nitrogen oxides, ozone, and radon can all have significant impact on occupants. These gases can be generated internally from smoking or combustion processes, operation of copiers and printers, operation of air cleaners, and poorly ventilated combustion equipment. Gases can also be introduced from the exterior via poor outdoor ventilation air, or in the case of radon, drawn up through the soil beneath and around the building. Cobeal factors all of these elements into its whole building design approach. 
  • Cobeal recognizes that individual susceptibility, the "human factor", can vary from person to person, and works with you to design a whole building system to meet your specific needs. 

Cobeal controls invisible particles, removing micro-airborne contamination is our expertise. Air volume, direction, pressurization, temperature, humidity, vibration and specialized filtration are closely linked. We specialize in achieving the highest level environmental conditions for your processes and production needs.

• Air Handling Units 
• Air Heaters
• Industrial Fans
• Air Curtains
• Channel Heat Exchangers
• HVAC Distribution Systems 
• Soundless Ventilation
• Clean Room Technology