As steam is generated from evaporation of water, remaining water in boiler becomes more and more concentrated. This must be drained away during blow down.

The challenge is to control draining to minimum.

Recovering Waste Heat from Blow down

Since it is necessary to blow down to control total dissolved solids in boiler water, methods can be adopted to recover some of heat back from drained hot water.

Blow down tanks, heat exchanger tubes and pumping arrangements can be fabricated to recover back some of heat back into boiler.

Stopping Dynamic Operation

Whenever a boiler starts or stops, a few minutes are spent running forced draft fan for purging combustion chamber of unburnt gases. This is a necessary step for safe operation of a boiler.

During this time heat from boiler water in shell or tubes will be lost to purging air.

To avoid this type of losses, it is better to maintain a steady firing condition in boilers.

Reducing Boiler Pressure

By reducing boiler pressure, some of heat losses through leakages or transmission may be reduced slightly. However there can be problems with boiler with reduced pressure. The boiler circulation may be upset and steam lines may have insufficient capacity and flow to transport low pressure steam.

Operating at Peak Efficiency

When operating two or more boilers, improved efficiency can sometimes be obtained by unequal sharing of load so that combined load operates at peak efficiency.

Preheating Combustion Air

Any heat loss from skin of boiler to boiler room can be utilized back for combustion. By preheating intake air combustion in furnace becomes more efficient.

Switching from Steam to Air Atomization

For burners with steam atomization, switching to air atomization will naturally result in less steam consumption overall and better boiler efficiencies. This is only applicable for heavy fuel oil burners.

Switching to Lower Cost Fuel

When comparing natural gas and fuel oil, if cost is same or more per BTU delivered, switch over to fuel oil.

The reason for this is that in combustion process, hydrogen combines with oxygen to form water. The latent heat of vaporization is lost when water vapor leaves boiler stack.

Fuels like natural gas with higher hydrogen to carbon ratio will lose this heat more than those with lower hydrogen-carbon ratio like fuel oil.

However one must also recognize that there will be increased maintenance, operating costs and greater need for more excess air in order to achieve complete combustion for fuel oil. In addition, soot deposits and incomplete combustion might also affect overall costs.

Some of ways mentioned above may not be feasible at all for your plant. Each of them may result in only a few percentage points of boiler efficiency improvement. However, if carried out carefully and with proper tools and instruments, they do add up to huge savings.

They have a refresh rate about 1,000 times faster than a traditional LCD, so they will be far superior for video applications. They have fewer parts than LCD or plasma and can be manufactured using a novel ink jet printing process. This promises to keep prices low as technology is implemented. It is expected to see sub 20" displays in stores by 2006 with larger units following one to two years later.

Other promising display technologies on horizon include SED (Surface-conduction Electron-emitter Display) and carbon Nanotube. SED was developed by Canon, who began research into technology in 1986. SED is basically same principle as CRT, however there are important differences. The most important from a consumer standpoint is thickness. An SED display is only an inch or two thick, depending upon screen size.

The basic construction is two glass plates separated by a vacuum. One of plates is coated with phosphors other is mounted with electron emitters. Electrons are ejected when a voltage of about 16 to 18 V is applied to emitters. These electrons are then accelerated by a higher voltage into a beam similar to that in a CRT display.

The visual advantages of SEDs are as for CRT displays, great color, deep black levels and quick motion response. These advantages, combined with slim form factor, low cost and small power requirement should make for a real winner.

A unit shown by Toshiba at a Japanese trade show in April of 2005 even had it’s contrast ratio up to an incredible 100,000 to 1 by significantly reducing black luminance. Even if specs were a bit inflated this would still amount to a fantastic contrast ratio, on order of 5 times that of a traditional CRT. Toshiba has indicated they will move to this technology for all displays over 40” by 2006.

One fly in SED ointment however. On April 21st, 2005 US firm Nano-Proprietary has filed a suit against Canon in U.S. District Court of Western District of Texas, alleging that surface (SED) televisions that Canon plans to release violates a licensing agreement signed 5 years ago between Japanese giant and Nano-Proprietary.

The pace of change in home theater and entertainment display market has just kept accelerating. There are some promising technologies around corner that will allow, as usual, higher performance, lower cost and more compact form factors. As prices for advanced technologies plunge and technology improves, it will make it even easier for average person to have a fantastic media system almost anywhere in their home.

Steve has 15 yrs in electronics. He is a CEDIA certified designer with ISF and THX certificates. Experience includes: installer and programmer; system designer; business unit director for an a/v importer; sales rep for a CE distributor; and principal of a $1.5M+ CEDIA firm. He's now senior sales engineer for Digital Cinema Design in Redmond, WA. See him at The Home Theater and Automation Guide