Highly Efficient Mechanical Systems

Question 1

What does GSHP stand for?

Answer 1

Ground-Source Heat pumps

Question 2

Explain how GSHPs work, and provide examples.

Answer 2

1. Use earth , ground water or both as heat sources in the winter, and as the heat sind in the summer.
2. Heat removed from earth by using a liquid, such as water, refrigerant, or an antifreeze solution. The liquid temp is raised by the pump and the heat is then transferred to indoor air.
3. In summer, the process is reversed; heat is taken from indoor air and transferred to the earth via the liquid.

Question 3

What is the coefficient of performance (COP) and cooling energy efficiency ratio (EER) ratings for GSHPs intended for ground-water or open-system applications?

Answer 3

COP ranges from 3.6 -5.2

EER ratings between 16.2 and 31.1

Question 4

What is the coefficient of performance (COP) and cooling energy efficiency ratio (EER) ratings for closed loop (not connected to groundwater) applications of GSHPs?

Answer 4

COP 3.1 - 4.9

EER 13.4 to 25.8

Question 5

What is the service life of GHSPs?

Answer 5

approx. 25 years

Question 6

What is the size range of GSHPs in kW (BTU/h)?

Answer 6

Units range in size from 5 kW to 40 kW (15 000 to 135 000 Btu/h)

Question 7

Describe GSHP integration in the home (ie heating,, cooling, DHW)

Answer 7

1. GSHPs are used with forced-air balanced distribution systems or hydronic heating systems.
2. Designed and installed to provide heating only, heating with passive cooling, or heating with active cooling
3. Water front he home water heater is pumped througha coil ahead of the GSHP condenser coil so that some of the heat that would have been dissipated at the condenser is used to heat water. Other GSHPs provide DHW on demand; the whole macine switches to providing DHW when required.

Question 8

What does ASHPs stand for?

Answer 8

Air source heat pumps

Question 9

How do ASHPs work?

Answer 9

ASHPs draw heat from outside air during the heating season and reject heat outside during the summer cooling season

Question 10

What are the two types of ASHPs?

Answer 10

Air to Air (most common)

Air to Water (used with hydronic heat distribution systems)

Question 11

Explain how air to air HPs work.

Answer 11

Extract heat fron air and then transfer heat to either the inside or outside of the house depending on the season.

Question 12

Explain how air to water HPs work.

Answer 12

Used in homes with hydronic heat distribution systems. During the heating season, these heat pumps take heat fron the outside air and then transfer it to the water in the hydronic distribution system. If cooling is provided during the summer, the process is reversed.

Question 13

What’s the best heat pump for residential retrofits?

Answer 13

Ductless mini-split heat pumps are ideal for retrofits in houses with hydronic or electric resistance baseboard heating. Up to 8 separate indoow wall-mounted units can be served by one outdoor section.

Question 14

What is the seasonal energy efficiency ratio (SEER) ratings and heat seasonal performance factor (HSPF) ratings for ASHPs in residential applications?

Answer 14

SEER 13-21

HSPF 6.3 to well over 8.6

Question 15

What is the service life of ASHPs?

Answer 15

15-20 years

Question 16

How are ASHPs integrated with other mechanical systems in the residential home?

Answer 16

1. ASHPs used with forced-air balanced distribution systems or hydronic heating systems (using an air-water heat pump), along with a heat recovery ventilator (HRV) or energy recovery ventilator (ERV).
2. More advanced designs of air-source heat pumps can provide domestic water heating (DWH).
3. ASHPs are also used in some home ventilation systems to recover heat from outgoing stale air and transfer it to either incoming fresh air or domestic hot water.

Question 17

What are the efficiencies for gas-fired condensing equipment?

Answer 17

1. Furnaces, boilers and hot wate heaters are equipped with condensing technology with efficiencies typically equal to or greater than 90 percent annual fuel utilization efficiency (AFUE) for furnaces and boilers and Energy Factor (EF) of .9 or thermal efficiency (TE) of 9- % or higher for hot water heaters

Question 18

How are gas-fired condensing equipments used in DHW systems?

Answer 18

Condensing gas-fired equipment can also be used for on-demand domestic water heaters. On-demand water heating systems have no tank and do not store heated water, thus eliminating water tank heat loss and increasing efficiency in DHW systems.

Question 19

How can gas-fired condensing equipment be integrated?

Answer 19

Some condensing gas-fired equipment can be used for both space and DHW heating (combo or combo systems)

Question 20

What does IMS stand for, and what is its function?

Answer 20

1. gas-fired Integrated Mechanical Systems (IMS)
2. group functions of space heating, water heating and heat recovery ventilation into a single package.
3. compatible with both forced air and radiant heating distribution approaches
4. residential gas-fired integrated mechanical systems provide: forced air space heating; domestic water heating; outside air ventilation with heat recovery

Question 21

What are the advantages of IMS systems?

Answer 21

1. higher energy efficiency
2. reduced carbon footprint
3. lower installation and maintenance costs