Chiller descaler

Chiller Descaler Why descale your chiller? Chillers, condensers and even cooling towers require maintenance due to the harsh mineral deposits such as calcium, lime, mud and rust that rob heat transfer efficiency. For instance, most major manufacturers of chiller equipment generally design chillers to operate with a maximum "thermal resistance" or "fouling factor" of 0.0005 inches of buildup. As a result, with only 0.0360 inches (about 1/32'') of deposit corresponds to an increase in energy costs of over 30%! Now ask yourself, "Can I afford not to do a RYDLYME cleaning on the chiller tower"? How to use RYDLYME descaler to descale your equipment: When isolating and cleaning the barrel on a tube chiller or cooling tower, RYDLYME will circulate through the water side and completely dissolve the scale in to a liquid suspension (like sugar in coffee), easily cleaning the hard to reach areas such as tube enhancements. Typically, cleanings can be accomplished in 4-6 hours depending on the severity of scale and volume of the barrel. RYDLYME can even be circulated via cooling tower to eliminate the need to shutdown the system! Preventative maintenance cleanings with RYDLYME will ensure optimal efficiency, bringing approach temperatures and pressures down to "as designed" specifications AND will help extend the life of the equipment. ------------------------ Mohammad Imran HVAC Engineer

Electrical (LOTO ) Lock Out Tag Out

Electrical Safety Lock Out Tag Out (LOTO) What is LOTO? Answer --) Electrical Lock Out Tag Out the physical restraint of all hazardous energy sources that supply power to a piece of equipment, machinery or system. LOTO also includes applying a Warning Tag on the physical restraint device. This documents the Authorized LOTO personnel and the date. LOTO operations must be done on all equipment, machinery or system Shut Downs before Authorized Personnel can perform repairs or service. Most equipment and machinery has an Energy Isolation Device. These devices are usually put into the off position to shut down the hazardous energy source. Physical restraints (Lock Out Devices) can be put onto the Energy Isolation Device and secured with padlocks. Examples of Lock Out Devices include: ball valve and gate valve lock outs, circuit breaker lockouts, plug and wall switch lock outs and pneumatic lock outs. The total shutdown and restraint of all hazardous energy sources including the safe release of stored hazardous energy (e.g. capacitors and pressure in a line) must be accounted for. Does LOTO apply to cord and plug equipment that may be used in the office or a lab? Answer -- Yes and No! NO, if the only energy source that powers the equipment is a cord and plug then the employee needs to remove the plug from the electrical power source and keep the cord and plug under his/her exclusive control while performing the service or maintenance task. Yes, LOTO does apply to cord and plug electrical equipment if there is another energy source (i.e.-a capacitor that stores electrical energy inside of the equipment) that could harm the employee if it was not identified and/or isolated prior to doing a service or maintenance task. Generally, stored electrical energy sources (i.e.-capacitors) are identified with an Electrical Shock Hazard Warning Label. What are hazardous energy sources and types of service and repair activities? Answer -- Some examples of hazardous energy sources include electrical, hydraulic, pneumatic, chemical, thermal or mechanical energy. Hazardous energy can also be stored (e.g. capacitors or gravity equipment, machinery or system components that are suspended, blocked or chocked). Service and repair activities may include but are not limited to: installing, setting up, adjusting, inspecting, lubricating, cleaning, making adjustments or tool changes. If I am responsible for the repairs or services on some equipment or machinery powered by a hazardous energy source, must I follow special requirements? Answer -- Yes! OSHA regulations and the University of Virginia Lock Out Tag Out (LOTO) Policy make LOTO procedures mandatory. Special requirements include the following: Step by step LOTO procedures must be developed, documented and followed for all equipment, machinery or system Shut Downs before Authorized Personnel can perform service or repairs. Authorized Personnel can include faculty, staff or students who are designated and qualified by the department to safely operate equipment, machinery or a system and; perform maintenance such as service and repairs. Authorized Personnel must be initially trained on LOTO procedures prior to performing Shut Downs. Personal padlocks, warning tags and lock out devices must be provided by the department and assigned to Authorized Personnel. Also, personnel affected by LOTO procedures and Shut Downs when working in controlled spaces (e.g. electrical power to work area is secured during renovation, demolition activities or abatement of hazardous materials) must be provided personal padlocks and warning tags. Are there any special precautions to take with equipment hardwired into a disconnect box? Answer -- Yes! If you shut off electrical power by turning off a Disconnect Switch you may be at risk of an unexpected failure of the equipment such as electrical arcing that can produce explosive forces. To avoid electrical risks and potential injuries read the Precautions below. NOTE: Individuals such as faculty, staff and students working in lab and shop environments, must follow these Special Procedures. These procedures will help to prevent injuries in the event there is a mechanical failure in the equipment. Take these precautions to avoid electrical safety risks prior to performing Lock Out Tag Out on "hard wired" equipment in a lab or a shop: Individuals such as faculty, staff and students are not to perform any repairs or service that involves working on energized conductors or; at any time coming into accidental contact with energized conductors that may become exposed if any electrical safety guard, shield or enclosure is removed. This type of work needs to be referred to: a qualified and licensed electrician (i.e. Facilities Management), or an equipment manufacturers' service technician. These individuals are authorized through special training and knowledge to perform work on equipment when it is energized or there is a potential risk of coming into contact with any of the electrical systems that can be energized. Please refer to the University's Electrical Safety policy SEC-029. Individuals in the shop or lab must be qualified (authorized by the department and trained) to perform the intended Lock Out procedure and assure all hazardous energy sources are shut off prior to doing the work. A qualified individual must have documented training and knowledgeable on the: specific hazards inherent in the equipment, the LOTO procedure and applicable LOTO devices to secure the equipment. What are the special procedures to follow when shutting off a disconnect switch? Safe procedures begins with wearing the right level of electrical personal protective equipment (PPE). PPE will help to prevent injuries if an electrical arc event occurs due to a faulty disconnect switch. This occurrence is expected to be minimal but you must be prepared and protected. You will need to wear plastic frame safety glasses (no metal) or impact resistant safety goggles (preferable) to protect your face from any shrapnel. You will also need to use hearing protection to protect your ears from explosive noise. Wear a heavy leather glove on your left hand and a long sleeve 100% cotton shirt or lab coat to protect your skin from burns. Do not wear any synthetic clothing such as rayon or polyester including fleece. These fabrics can exacerbate the level of burn injuries in the event of an electrical arc flash by embedding into the skin. This goes for what you are wearing underneath the long sleeve shirt or lab coat. Donned in your PPE, use the "left hand rule" to operate the disconnect switch into the off position. Twist your face and torso away and use your left hand to turn the safety switch off. This helps to prevent a direct injury to the face, eyes, and front of torso in the case of a sudden mechanical failure inside the disconnect box. Next, operate the power switch of the equipment or machinery to verify the power is off. The electrical disconnect switch must be locked out by the authorized individual shutting off the power as well as any other authorized individual who will perform work on the equipment. Remember! A qualified licensed electrician must perform services or repairs on electrical equipment where there is any risk of coming into contact with energized conductors. Are there resources available to help me develop appropriate LOTO procedures? Answer -- Yes! Equipment manufacturers, their service representatives or; the Equipment Operator’s Manual, can provide information on how to safely isolate the equipment’s energy source(s) during service or maintenance activities. Personnel must be authorized by the Department to perform this task; their qualification should include training and proficiency to perform the task. Do I have to document anything before I shut down equipment or machinery for service and repairs? Answer -- Yes! LOTO procedures must be written down in an easy to understand step by step sequence that accounts for the safe Shut Down of all hazardous energy sources including stored energy. The goal is consistent and safe Shut Downs by all Authorized Personnel. Written LOTO procedures are the foundation of LOTO training. This training must be documented and is required to Authorize and Qualify personnel to perform Shut Downs. Download the LOTO Procedure Form word | pdf Do employees need to be trained before they can shut down and lock out equipment and machinery for repairs? Answer -- Yes! Only Authorized Personnel can Shut Down and lock out equipment powered by hazardous energy sources. Personnel are Authorized and Qualified through training on LOTO regulatory requirements and LOTO procedures for the equipment or machinery they have been assigned to work on. Personnel affected by Shut Downs because they are operators of the equipment/machinery or they must work in a controlled work area must also participate in LOTO training. If I am responsible for several employees doing a Shut Down on equipment/ machinery for some service or repairs, does each employee have to perform LOTO? Answer -- Yes! The regulations refer to this as multiple or "group lock out". Special procedures for "group lock out" must be included in the mandatory LOTO procedure. Special "group lock out" devices are available that can hold multiple padlocks. This assures each person’s safety until the work by all Authorized Personnel has been completed. All personnel participating in a "group lock out" must be trained on the LOTO procedure and the special "group lock out" procedures. Do employees need to wear personal protective equipment during LOTO Operations? Answer -- Most likely yes. Shutting Down electrical energy sources could result in arcs or contact with energized parts. Safety glasses or faceshields to protect from potential electrical arcs or explosions and insulated gloves rated for the voltage are advisable. Only qualified electricians can shut down electrical energy sources. Working around thermal energy sources such as medium and high pressure steam may require clothing and/or thermal blankets to protect from burn hazards. These are only a couple of examples. Contact EHS for assistance on appropriate personal protective equipment for your specific operation. Which OSHA regulations require LOTO? HOISTING EQUIPMENT 29 CFR 1910.179 -- Overhead and Gantry Cranes -- The power supply to the runway conductors of the hoisting mechanisms needs to be controlled by a fixed switch or circuit breaker that is accessible from the floor. The switch must be locked in the open position. Cab operated cranes or hoisting mechanisms must have the switch or circuit breaker located within easy reach of the operator. Controllers-must be in off position. Main or emergency switch-locked in open position. Out of Order signs must be visibly posted. POWERED INDUSTRIAL TRUCKS 29 CFR 1910.178 -- Disconnect the battery before making any repairs to the trucks electrical system. WOODWORKING MACHINERY 29 CFR 1910.213 -- Power driven woodworking machines must have a disconnect switch that can be locked in the off position during repairs or adjustments. WELDING 29 CFR 1910.252 -- Must purge/clean all tanks, vessels, barrels, drums - prior to welding& cutting to prevent explosion and generation of flammable/toxic gases. All pipelines to the drum or vessel must be disconnected and blanked. ELECTRICAL STANDARD 29 CFR 1910.333 Can have two written programs that address electrical Lock out Tag out or one that complies with 29 CFR 1910.147 if it covers sections (c)thru(f) and the inherent electrical hazards. Must treat conductors or electrical parts that have not been locked and tagged out as "energized". Only qualified electricians can work on energized systems. Cannot substitute interlocks on electrical equipment for lockout/tagout. Must discharge capacitors. High capacitance elements must be short-circuited and grounded. ----------------- Mohammad Imran HVAC Engineer

Bearing & Types of Bearing

bearings A mechanical bearing is a component used between two parts that allows rotational or liner movement, reducing friction and enhancing performance to save energy. Both metal and plastic bearings can be found everywhere, from refrigerators to computers to the 100 or so bearings found in your car. The concept behind them is a simple one: things roll better than they slide. Without bearings, the wheels in your car would rattle, the transmission gear teeth wouldn’t be able to mesh, and the car wouldn't run smoothly. They are composed of a smooth inner and outer metal surface for metal balls to roll against. The balls or rollers help “bear” the load and the device functions more efficiently. There are many different types of bearings, each used for specific purposes and designed to carry specific types of loads, radial or thrust. Here, we’ll look at the 6 most popular types: plain bearings, rolling element bearings, jewel bearings, fluid bearings, magnetic bearings, and flexure bearings. 1) Plain Bearings Plain bearings are the simplest type of bearing and are composed of just the bearing surface with no rolling elements. They have a high load-carrying capacity, are generally the least expensive and, depending on the materials, have much longer lives than other types. 2) Rolling Element Bearings Rolling element bearings place balls or rollers between two rings – or “races” – that allows motion with little rolling resistance and sliding. These bearings include ball bearings and roller bearings. Ball bearings are the most common type of rolling element bearing. These bearings can handle both radial and thrust loads but are usually used where the load is relatively small. Because of its structure, there is not a lot of contact with the balls on the inner and outer races. If the bearing is overloaded the balls would deform and ruin the bearing. Roller bearings are able to handle a much heavier, radial load, like conveyor belts, because they don’t use balls. Instead, they have cylinders allowing more contact between the races, spreading the load out over a larger area. However this type of bearing is not designed to handle much thrust loading. 3) Jewel Bearings Jewel bearings are plain bearings with a metal spindle that turns in a jewel-lined pivot hole. They carry loads by rolling the axle slightly off-center and are usually used in mechanical watches or clocks. This is due to their low and predictable friction that improves watch accuracy. 4) Fluid Bearings Fluid bearings support their load using a thin layer of gas or liquid and can be classified into two types: fluid-dynamic bearings and hydrostatic bearings. Fluid-dynamic bearings use rotation to form the liquid into a lubricating wedge against the inner surface. In hydrostatic bearings, the fluids – usually oil, water, or air – rely on an external pump. Fluid bearings are used in high load, high speed or high precision applications that ordinary ball bearings either couldn’t handle or would suffer from increased vibration and noise. 5) Magnetic Bearing Magnetic bearings support moving parts without physical contact, instead relying on magnetic fields to carry the loads. They require continuous power input to keep the load stable, thus requiring a back-up bearing in the case of power or control system failure. Magnetic bearings have very low and predictable friction and the ability to run without lubrication or in a vacuum. They are increasingly used in industrial machines like turbines, motors, and generators. 6) Flexure Bearing A typical flexure bearing is one part joining two others, like a hinge, in which motion is supported by a load element that bends. These bearings require repeated bending, so material selection is key. Some materials fail after repeated bending, even at low loads, but with the right materials and bearing design the flexure bearing can have an indefinite life. Another notable characteristic of this bearing is its resistance to fatigue. Many other bearings that rely on balls or rollers can fatigue as the rolling elements flatten against. -----'-------------- Mohammad Imran HVAC Engineer

Heat Load calculation in term of HVAC

Heat load or heat gain A building or room gains heat from many sources. Inside occupants, computers, copiers, machinery, and lighting all produce heat. Warm air from outside enters through open doors and windows, or as ‘leakage’ though the structure. However the biggest source of heat is solar radiation from the sun, beating down on the roof and walls, and pouring through the windows, heating internal surfaces. The sum of all these heat sources is know as the heat gain (or heat load) of the building, and is expressed either in BTU (British Thermal Units) or Kw (Kilowatts). For an air conditioner to cool a room or building its output must be greater than the heat gain. It is important before purchasing an air conditioner that a heat load calculation is performed to ensure it is big enough for the intended application. Heat load calculations There are several different methods of calculating the heat load for a given area: Quick calculation for offices For offices with average insulation and lighting, 2/3 occupants and 3/4 personal computers and a photocopier, the following calculations will suffice: Heat load (BTU) = Length (ft.) x Width (ft.) x Height (ft.) x 4 Heat load (BTU) = Length (m) x Width (m) x Height (m) x 141 For every additional occupant add 500 BTU. If there are any additional significant sources of heat, for instance floor to ceiling south facing windows, or equipment that produces lots of heat, the above method will underestimate the heat load. In which case the following method should be used instead. A more accurate heat load calculation for any type of room or building The heat gain of a room or building depends on: The size of the area being cooled The size and position of windows, and whether they have shading The number of occupants Heat generated by equipment and machinery Heat generated by lighting By calculating the heat gain from each individual item and adding them together, an accurate heat load figure can be determined. Step One Calculate the area in square feet of the space to be cooled, and multiply by 31.25 Area BTU = length (ft.) x width (ft.) x 31.25 Step Two Calculate the heat gain through the windows. If the windows don’t have shading multiply the result by 1.4 North window BTU = Area of North facing windows (m. sq.) x 164 If no shading, North window BTU = North window BTU x 1.4 South window BTU = Area of South facing windows (m. sq.) x 868 If no shading, South window BTU = South window BTU x 1.4 Add the results together. Total window BTU = North window + South window Step Three Calculate the heat generated by occupants, allow 600 BTU per person. Occupant BTU = number of people x 600 Step Four Calculate the heat generated by each item of machinery - copiers, computers, ovens etc. Find the power in watts for each item, add them together and multiply by 3.4 Equipment BTU = total equipment watts x 3.4 Step Five Calculate the heat generated by lighting. Find the total wattage for all lighting and multiply by 4.25 Lighting BTU = total lighting watts x 4.25 Step Six Add the above together to find the total heat load. Total heat load BTU = Area BTU + Total Window BTU + Occupant BTU + Equipment BTU + Lighting BTU Step Seven Divide the heat load by the cooling capacity of the air conditioning unit in BTU, to determine how many air conditioners are needed. Number of a/c units required = Total heat load BTU / Cooling capacity BTU

VRF&VRV

VRV or VRF ? What’s the difference between VRV and VRF? Many people who ask this question, mistakenly interpret it as 2 different HVAC technologies. Actually, those are two different terms for the same type of HVAC technology. Based on Inverter technology compressors, the first VRV HVAC systems were invented by Daikin during the early 1980’s. As a technology leader in the HVAC industry, Daikin had registered the VRV term (which stands for Variable Refrigerant Volume1) as an official trademark. All other companies use VRF (Variable Refrigerant Flow2) for their similar HVAC systems. Eventually, VRF is the more common term for these types of systems, and this is the term that will be used for the rest of the article. Wish to integrate your VRF to Home Automation system? Check out our simple solutions. So what is VRF? It can easily be related to as the “Rolls Royce” of Air Conditioning Systems. It’s a very sophisticated technological air conditioning system, based on several principles: Refrigerant only – where refrigerant is the only coolant material in the system (in contrary to the chilled water systems, where refrigerant is used for cooling/heating the water that is circulated throughout the whole system). Inverter compressors that allow lowering power consumption with partial cooling/heating loads. Several air handlers (indoor units) on the same refrigerant loop / circuit. Ability of modular expansion (especially applicable for large projects, that can grow in stages). Typical VRF system structure A typical system consists of an outdoor unit (comprising one or multiple compressors), several indoor units (often and mistakenly called “fan coils”), refrigerant piping, running from the outdoor to all indoors, using Refnet Joints (copper distributors in pipes) and communication wiring. VRV / VRF HVAC connectivity diagam Communication wiring consists of a 2 wired cable, chained from the outdoor to all indoors, creating an internal closed loop network, that is an essential part of any VRF installation. As for the Control, each indoor is controlled by its own wired control panel, while there are some possibilities for wireless remotes (IR) and centralized controllers, enabling controlling all indoors from one location. How does VRF HVAC work? The operation logic of the VRF is fully built-in inside the system and is proprietary for each VRF manufacturer. The system gets inputs from the user (e.g. desired comfort temperature) and from the surroundings (outside ambient temperature), and according to that data it implements its logic in order to get to the desired comfort conditions, utilizing optimal power consumptions. The ability to adjust itself to the outdoor conditions is one of the main factors that makes these systems so efficient, compared to the traditional water cooled systems, based on chillers and fan coils. Now, let’s dive in, and see how it works in details. Let’s take as an example a typical VRF installation, with one outdoor unit and multiple indoors. At the beginning, the system is in standstill condition (everything is turned off). Once a user turns one of the indoors “ON” by its local remote, the outdoor “gets noted” regarding it, and starts working. At this point, it will examine the outdoor conditions (temperature), the operating indoor requirements (operation mode, set point temperature), and will operate the compressor at the exact level, required to comply with the indoor requirements. When another indoor unit is turned on, the outdoor recalculates the requirements from all the indoors, and will increase the compressor’s output, according to the required level of demand. This process is constantly occurring with any change, performed in the HVAC system. As described, this system is fully automatic, and regulates its power consumption based on the demand arriving from the indoor units and outside prevailing conditions. User can have influence on the desired indoor comfort conditions, modifying: Operation mode (on/off), Operation state (Cool/Heat/Fan/Dry/Auto), setpoint temperature, fan speed (high/medium/low/auto). Controlling those parameters is the only thing required for proper operation, and the only thing that is required for proper integration with the VRF system. VRF System types Cooling only systems (less popular) – those systems can only cool. Heating is not available. Fan and Dry modes are available for each indoor unit independently. Heat Pump systems (most popular) – all the indoor units can either heat, or cool (not at the same time). Fan and Dry modes are available for each indoor unit independently. Heat Recovery systems (less popular) – those systems are the most sophisticated ones, where cooling and heating may be available by each indoor unit, independently, at the same time.

VFD

A Variable Frequency Drive (VFD) is a type of motor controller that drives an electric motor by varying the frequency and voltage supplied to the electric motor. Other names for a VFD are variable speed drive, adjustable speed drive, adjustable frequency drive, AC drive, microdrive, and inverter. ---------------------- Mohammad Imran HVAC Engineer

Compressor Over load

The overload relay is a protection device used in the compressor circuit on your refrigerator. Power is applied to the compressor motor windings through the overload device, and the relay is used to add the start winding in the circuit until the compressor is at running speed. ----------------------- Mohammad Imran HVAC Engineer

What is surge

In a centrifugal compressor, 'surge' is a name given to a dangerously unstable gas condition in the compressor and condenser. Put simply, it occurs when the forward compression thrust of gases in the compressor wheel falls below the critical velocity of the gas to flow forward through the condenser.Apr

Cause of surging in chiller

The flow separation will eventually cause a decrease in the discharge pressure, and flow from suction to discharge will resume. Surging can cause the compressor to overheat to the point at which the maximum allowable temperature of the unit is exceeded. ... This is defined as the surge cycle of the compressor.. --------------------- Mohammad Imran HVAC Engineer

Water treatment process

Community Water Treatment Drinking water supplies in the United States are among the safest in the world. However, even in the U.S., drinking water sources can become contaminated, causing sickness and disease from waterborne germs, such as Cryptosporidium, E. coli, Hepatitis A, Giardia intestinalis, and other pathogens. Drinking water sources are subject to contamination and require appropriate treatment to remove disease-causing agents. Public drinking water systems use various methods of water treatment to provide safe drinking water for their communities. Today, the most common steps in water treatment used by community water systems (mainly surface water treatment) include: Figure illustrating the water treatment cycle, showing coagulation, sedimentation, filtration, and disinfection Figure courtesy of EPA Coagulation and Flocculation Coagulation and flocculation are often the first steps in water treatment. Chemicals with a positive charge are added to the water. The positive charge of these chemicals neutralizes the negative charge of dirt and other dissolved particles in the water. When this occurs, the particles bind with the chemicals and form larger particles, called floc. Sedimentation During sedimentation, floc settles to the bottom of the water supply, due to its weight. This settling process is called sedimentation. Filtration Once the floc has settled to the bottom of the water supply, the clear water on top will pass through filters of varying compositions (sand, gravel, and charcoal) and pore sizes, in order to remove dissolved particles, such as dust, parasites, bacteria, viruses, and chemicals. Disinfection After the water has been filtered, a disinfectant (for example, chlorine, chloramine) may be added in order to kill any remaining parasites, bacteria, and viruses, and to protect the water from germs when it is piped to homes and businesses.

Role of vacuum in RAC

A vacuum is maintained in the condenser so that steam can easily flow and more work can be extracted from the steam in the turbine. How does the condensate extraction pumps take suction from such a low pressure condensor. ---------------'-----' Mohammad Imran HVAC Engineer