Tag: HVAC

Benefits and Drawbacks of Displacement Ventilation

Benefits and Drawbacks of Displacement Ventilation

Benefits and Drawbacks of Displacement Ventilation

11/09/17

“What are the benefits and drawbacks of displacement ventilation?”

 

Displacement ventilation is a technology with quite a bit of potential behind it. These systems typically provide better indoor air quality through natural ventilation. This also saves large amounts of energy and gives it lower airflow rates for the same or better quality. The lacks of mechanical parts improve acoustics which lowers pressure losses through diffusers. Unfortunately, the novelty of these systems means that they are usually not well known by contractors. Their specialized geometry requires coordination of building features and diffuser locations, require larger quantities of air where cooling loads are needed, and the ceiling based filtering systems also means that higher ceilings will be needed.

Displacement Ventilation

Displacement Ventilation

Displacement Ventilation

11/08/17

“How can we make an air ventilation systems that relies upon pulling natural air?”

 

Air ventilation systems typically rely upon controlling artificial air to supply co into a surrounding environment. However, this can consume a large amount of energy and can make a large amount of noise. So how can we use our engineering mindsets to fix this problem? Well, we know that at all times buildings will have clean air surrounding it. And if we could get some of this into our building, then it would make the internal environment much nicer. So what if we were to use diffusers near the floor of an edifice to siphon outside air at low velocities into the interior, and then let the waste heat rise and recycle it into the exterior? Well, this is the fundamental concept behind displacement ventilation. Displacement ventilation is quite popular in Scandinavian countries.

Deep water source cooling

Deep water source cooling

Deepwater source cooling

11/07/17

“How can we use nature to make an efficient AC system?”

 

Many HVAC systems work by using chilled water to control the built environment. However, chilling this water can expend a massive amount of energy, as can providing a reliable heat sink. So how can we use our engineering mindset to make this system more efficient? Well, if we were to take our water from a source that is already chilled and use it as a heat sink, we will be able to have massive energy savings. One source of very cold water comes from deep water areas, such as lakes and oceans. So what if were to simply use this chilled water for our system? Well, this is known as deep water source cooling and is a most innovative way to solve the heat-energy problem. An example of these systems in action is Cornell University’s Lake Source Cooling project in Ithaca, New York.

Post-Occupancy Evaluation

Post-Occupancy Evaluation

Post-Occupancy Evaluation

11/05/17

“How do we evaluate buildings after they have been built and used?”

 

Modern Buildings are designed to function in a certain way. However, after they have been built, unforeseen factors can disrupt things and cause inefficiencies. So how can we evaluate buildings in an effective and rigorous manner after they have been constructed? Well, after many years of research, building professionals in both the U.S and Scotland have developed something called a Post-Occupancy Evaluation, which involves authorized individuals to arrive onsite an perform audits. Once an evaluation has been done, further action can be commenced to bring the unit to full operation

ASHRAE Standard 55

ASHRAE Standard 55

ASHRAE Standard 55

11/05/17

“What exactly specifies what is the proper working conditions for buildings?”

 

Proper working conditions are vital to the operation of the modern world. And one of these conditions includes thermal comfort, which consists of temperature, thermal radiation, humidity, and airspeed. And because buildings are constructed in all sorts of operating environments, we must need some form of standard that stipulates what are the proper indoor conditions. Well, after much debate, the good engineers of the American Society of Heating, Refrigerating and Air-Conditioning Engineers have developed a protocol known as ASHRAE Standard 55, which takes in the operative temperature, wet bulb temperature, humidity ratio, and relative humidity to create a thermal comfort zone. You can see a demonstration of this in action at http://comfort.cbe.berkeley.edu/, provided by the Center for the Built Environment at the University of California, Berkeley

Variable Speed Drives

Variable Speed Drives

Variable Speed Drives

11/04/17

“How can we implement powerful yet controllable motors for industrial processes?”

 

Industrial motors are marvelous for being able to coordinate highly intricate processes in an efficient manner. However, sometimes we may need to adjust the speed on these machines using traditional models. So how can we use our knowledge of industrial control systems and our engineering mindset to achieve this? Well, let’s get down to the basics. We know that controllers can be used to provide feedback to electric devices, such as motors. So what if we were to simply implement a controller based motor into industrial processes? Well, this is the fundamental idea behind variable speed drives, which are commonly used as energy savers in pump and fan appliances.

Radiators

Radiators

Radiators

11/01/17

“How can we achieve radiative heating?”

 

Radiative heating has a plethora of energy and ergonomic benefits. However, how can we put this idea into practice? Well, we know that we can use heat exchangers to transfer heat from one medium to another. So what if we were to simply build a specialized model to transfer heat to the surrounding atmosphere? Well, this mechanism is known as a radiator and has become one of the most common HVAC appliances in the world.

Advantages and Disadvantages of Chilled Beams

Advantages and Disadvantages of Chilled Beams

Advantages and Disadvantages of Chilled Beams

10/31/17

“What are the advantages and disadvantages of chilled beams?”

 

Chilled beams are a most innovative approach to building climate control that comes with their own advantages and disadvantages. Their water-based design allows them to be run at lower costs and can work in smaller building environments. When the University of North Carolina – Chapel Hill switched one of their buildings to chilled beams, they were able to see a cost reduction of 20%! However, these systems have their drawbacks as well. Because Chilled Beams work by absorbing rising hot air, rooms with these systems must not be too large to ensure optimal use. In addition, the circulative nature of their operation means that hospitals in the U.S are unable to implement such systems due to health concerns. When choosing whether or not to implement Chilled Beams, one must be observant of their qualities and choose wisely.

Chilled Beams

Chilled Beams

Chilled Beams

10/30/17

“How can we make Air Conditioning without using any electricity?”

 

Air conditioning systems are excellent for cooling a building, but they come at a steep price in terms of a large electricity usage. So how can we use our engineering mindsets to solve this problem? Well, let’s start by thinking about two fundamental physical heat phenomena. The first involves one of the primary components of practical heat transfer, heat exchangers, which can cause two different fluids to change their temperatures by placing them right next to each other. The second principle involves the fact that cold air sinks and hot air rises. So what if we were to cycle cooled water near the ceiling of a room to cool the surrounding air, therefore letting the hotter air rise and decreasing the temperature of the lower parts of the room? Well, this is the fundamental idea behind a technology called Chilled Beams and is a very popular setup in Europe and Australia (and increasingly in North America!)