## How is OTTV calculated?

The OTTV of an entire building is calculated by the weighted average of the OTTVs of the external walls and the roof of a building. Some countries in the Central America, including Jamaica and Ivory Coast, had developed their building energy standards using OTTV as a part of the requirements [4].

### What is OTTV?

Overall thermal transfer value (OTTV) is one aspect of energy conservation. General approach. 1.2 An OTTV is a measure of the energy consumption of a building envelope.

#### How do I reduce OTTV?

So, the OTTV can be reduced by using lower wall U-value and lower wall absorption. Wall U-value and wall absorption can be reduced by thermal insulation the concrete brick for wall and using the light colour of wall external surface finish. Moreover introducing shades and coating on glass can reduce solar heat gain.

What is OTTV and RTTV?

‘Applications of Overall Thermal Transfer Value (OTTV) and Residential Thermal Transfer Value (RTTV) in. buildings’ ‘Cases sharing on passive design for energy reduction and energy efficient building layout’

What is overall thermal transfer value?

Overall Thermal Transfer Value (OTTV) is a measure of average heat gain into a building through the building envelope. It is a widely adopted measure in many countries for enhancing energy-efficient building design.

## What are the limitations of the OTTV standards in Hong Kong?

Limitations of the OTTV Standard in Hong Kong The biggest limitation of the OTTV method is that it only deals with the building envelope and does not consider other aspects of building design (such as lighting and air-conditioning) and the coordination of building systems to optimize the combined performance.

### What is the U value of concrete?

Calculating U-value

Material Thickness Conductivity (k-value)
Outside surface
Clay bricks 0.100 m 0.77 W/m⋅K
Glasswool 0.100 m 0.04 W/m⋅K
Concrete blocks 0.100 m 1.13 W/m⋅K

#### What does RTTV mean?

RTTV

Acronym Definition
RTTV Roof Thermal Transfer Value (energy)
RTTV Rheinhessischer Tisch-Tennis-Verband (German: Rhine Hessian Table Tennis Association)

What is Au value?

Thermal transmittance, also known as U-value, is the rate of transfer of heat through a structure (which can be a single material or a composite), divided by the difference in temperature across that structure. The units of measurement are W/m²K. The better-insulated a structure is, the lower the U-value will be.

What is an envelope in construction?

At its simplest definition, the building envelope is the exterior or shell of a building that repels the elements. It is the physical separator between the conditioned and unconditioned environment of a building including the resistance to air, water, heat, light, and noise transfer.

## What is Envelope Thermal Transfer Value?

Envelope Thermal Transfer Value (ETTV) These are: heat conduction through opaque walls, heat conduction through glass windows, solar radiation through glass windows. 4.2 These three components of heat input are averaged over the whole. envelope area of the building to give an ETTV that represents the thermal.

### Why is overall thermal transfer value ( ottv ) important?

This paper discusses the significance of the Overall Thermal Transfer Value (OTTV) controls as a means of enhancing energy efficiency of buildings. OTTV is a measure of heat gain into the building through the building envelope. It also acts as an index for comparing the thermal performance of buildings.

#### What does ottv stand for in building envelope?

OTTV stands for ‘Overall Thermal Transfer Value’. It is a value that indicates the average rate of heat transfer into a building through the building envelope. Building envelope The term building envelope refers to the outermost layer of a building.

What is the overall thermal transfer value of a building?

Overall thermal transfer value is a measure of average heat gain transferring into a building through the building envelope and can be adopted for comparison of thermal performance among different building designs.

When was the use of ottv first used?

The use of OTTV was firstly proposed by the American Society of Heating, Refrigerating and Air-conditioning Engineers (ASHRAE) in 1975 [7]. It is a measure of the average heat gain into a building through the building envelope and can be used for comparing the thermal performance of buildings.

How is OTTV calculated? The OTTV of an entire building is calculated by the weighted average of the OTTVs of the external walls and the roof of a building. Some countries in the Central America, including Jamaica and Ivory Coast, had developed their building energy standards using OTTV as a part of the requirements [4].…