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The drawing shows the draft design of the ground floor plan of a new dwelling house - Leaving Cert Construction Studies - Question 10 - 2020
Question 10
The drawing shows the draft design of the ground floor plan of a new dwelling house. The homeowners propose to install a Mechanical Ventilation with Heat Recovery (M... show full transcript
Worked Solution & Example Answer:The drawing shows the draft design of the ground floor plan of a new dwelling house - Leaving Cert Construction Studies - Question 10 - 2020
Step 1
Discuss in detail, using notes and freehand sketches, three considerations that should be taken into account when designing a MVHR system for a domestic house.
Answer
Considerations for Designing a MVHR System
1. System Design and Location
- The MVHR unit should be placed in an internal corner of the house, ideally away from areas where it could be obstructed by furniture.
- It's crucial to ensure that the inlet and induction pipes are not on a similar surface; this minimizes the risk of stale air re-entering the system.
- The design should focus on optimizing energy efficiency and reducing heat loss by strategically positioning the unit to take advantage of the building envelope's insulation.
2. Year-Round Operation and Performance
- Ensure the system is capable of operating throughout the year by incorporating a summer by-pass valve. This will prevent discomfort during hotter months by allowing fresh air circulation without excessive heating.
- Regular maintenance checks should be factored into the design to ensure long-lasting efficiency and functionality.
3. Noise Control and Air Quality
- The MVHR unit should be installed away from sleeping areas to minimize noise disturbance.
- Use anti-vibration mounts and solid flooring to reduce any noise transmission, contributing to improved air quality and comfort for occupants.
Step 2
Draw a line diagram of the given house plan. Show on your diagram the location of the MVHR unit and a typical layout for the system ducting. Indicate clearly the direction of the airflow in the ducts.
Answer
Line Diagram Description
- Location of MVHR Unit: Place the MVHR unit in the utility area closest to the kitchen to facilitate easy access and maintenance.
- Duct Layout:
- Supply Ducts: Extend ducts from the MVHR unit to the main living areas (kitchen, living room, bedrooms).
- Extract Ducts: Connect from high moisture areas (bathrooms, kitchen) back to the MVHR.
- Airflow Direction: Clearly label arrows on the diagram to show:
- Blue arrows for incoming fresh air from outside.
- Red arrows for stale air being extracted back to the MVHR unit.
System Operation Description
- The MVHR system works by continuously exchanging stale indoor air with fresh outdoor air, ensuring indoor air quality is maintained while minimizing heat loss.
Step 3
Describe how the MVHR system works.
Answer
Working of an MVHR System
A Mechanical Heat Recovery Ventilation (MVHR) system operates as follows:
- Air Supply: Fresh air is drawn into the home via ducts, while stale indoor air is mechanically extracted back to the unit.
- Heat Exchange Process: The MVHR unit features a heat exchanger; as the stale air is expelled, it transfers the heat to incoming fresh air.
- Filtration: Before exiting into the living space, the incoming fresh air passes through a filter to remove pollutants such as dust and pollen, ensuring the supply is healthy for occupants.
- Continuous Operation: This process continually circulates air, providing a constant supply of fresh air while removing excess moisture and odors, resulting in improved indoor air quality for all occupants.
Step 4
Discuss two advantages of installing a MVHR system into a domestic house.
Answer
Advantages of Installing a MVHR System
1. Improved Air Quality
- MVHR systems enhance indoor air quality by filtering out contaminants like dust, pollen, and other allergens, leading to a healthier living environment for occupants.
- Continuous air movement helps reduce the risk of mold and moisture buildup, contributing to overall home health.
2. Energy Efficiency
- By exchanging heat between the outgoing stale air and incoming fresh air, MVHR systems can recover up to 95% of the energy typically lost, resulting in lower energy bills.
- This high efficiency supports sustainable living practices by reducing the carbon footprint of the household.